Complaint sub-issue: Problem using a debit or ATM card

Dear Sir or Madam, I am in urgent need of your help with a financial dispute with my bank over unauthorized transactions. 
I need your help and assistance for a fair conclusion of my case with Key Bank. I did not receive the full credit amount for unauthorized transactions on my Key Bank checking account for multiple XXXX transactions. Here is the detailed development of the case : In the evening of XX/XX/XXXX after work, I tried to withdraw {$20.00} from my ATM debit card at Key Bank at : XXXX XXXX XXXX XXXX, XXXX OR XXXX. The ATM refused to give me the money, displaying a message explaining that I did not have enough funds in my account. In shock, I asked to check my account balance and was very surprised to learn that I only had XXXX cents instead of some close to {$5000.00} that I should have had. I used this debit card and account exclusively to pay rent, utility bills, and in-store only if they do not accept credit cards. My salary gets direct deposited to this account so at any given point I am quite aware of the balance it should have. With the information of {$0.00} balance, I immediately went to the XXXX XXXX XXXX located next to Key Bank and through the Internet I printed out from my bank account all transactions from the moment of opening my account in the summer of XXXX through that current moment. Thus, I found that periodically unauthorized purchases were made on my account from the XXXX site as follows : - on XXXX XXXX : 3 x transactions of {$1.00} - a total of {$5.00} - on XXXX XXXX : 2 x transactions of {$4.00} and 6 x transactions of {$1.00} - a total of {$21.00} - on XXXX XXXX : 2 x transactions of {$4.00} and 1 x transaction of {$1.00} - a total of {$11.00} - on XXXX XXXX : 6 x transactions of {$1.00} and 1 transaction of {$0.00} - a total of {$12.00} - on XXXX XXXX : 28 transactions of {$0.00}, 2 x transactions of {$4.00} and 7 x transactions of {$1.00} - a total of {$51.00} - on XXXX XXXX : 15 x transactions of {$0.00} - a total of {$14.00} - on XXXX XXXX : 12 x transactions of {$0.00} and 7 x transactions of {$1.00} - a total of {$25.00} - on XXXX XXXX : 38 x transactions of {$0.00} and 1 x transaction of {$4.00} - a total of {$42.00} - on XXXX XXXX : 8 x transactions of {$1.00}, 31 x transactions of {$4.00}, 11 x transactions of {$9.00} and 1 x transaction of {$14.00} - a total of {$290.00} - on 4 XXXX : 20 x transactions of {$4.00}, 5 x transactions of {$1.00} and 4 x transactions of {$9.00} - a total of {$140.00} - on XXXX XXXX : 7 x transactions of {$4.00}, 2 x transactions of {$1.00} and 1 transaction of {$9.00} - a total of {$48.00} - on XXXX XXXX : 7 x transactions of {$4.00}, 11 x transactions of {$9.00} and 2 x transactions of {$19.00} - a total of {$180.00} - on XXXX XXXX : 38 x transactions of {$4.00}, 4 x transactions of {$9.00}, 2 x transactions of {$1.00}, 2 x transactions of {$0.00} and 1 transaction of {$14.00} - a total of {$250.00} - on XXXX XXXX : 28 x transactions of {$4.00} and 5 x transactions of {$1.00} - a total of {$140.00} - on XXXX XXXX : 20 x transactions of {$4.00} - a total of {$99.00} - on XXXX XXXX : 10 x transactions of {$9.00} and 10 x transactions of {$19.00} - a total of {$290.00} - on XXXX XXXX : 3 x transactions of {$4.00}, 13 x transactions of {$19.00} and 2 x transactions of {$9.00} - a total of {$290.00} - on XXXX XXXX : 20 x transactions of {$99.00}, 4 x transactions of {$19.00}, 6 x transactions of {$9.00}, 4 x transactions of {$4.00}, 12 x transactions of {$49.00}, 2 x transactions of {$0.00}, 1 transaction of {$49.00} and 1 transaction of {$1.00} - a total of {$2800.00} On the same date ( XX/XX/XXXX ) in the process of " pending '' the following transactions, which were subsequently reported as completed on XX/XX/XXXX : 5 x transactions of {$0.00}, 1 transaction of {$9.00}, 1 transaction of {$19.00} and 1 transaction of {$99.00} - a total of {$130.00} The sum of all these transactions is {$4900.00} I did not get any alert of suspicious activity even though the way these transactions are in a very strange repetitive amounts, so only when my balance alert came up is when I looked and saw all these. 
I immediately called the bank and asked to block my debit card and account when they said someone was using it and making these charges. I explained that these were unauthorized transactions that I had just learned about. I could not understand well what they told me, but said I will go to a bank the next day to get this figured out. I then contacted my friend, who offered to help me file a claim case and a report of the unauthorized transactions with Key Bank fraud department right away to make sure they understood me and got my account and card blocked. She understands and speaks English much better than me. I waited for her to come to me and around XXXX XXXX  ( Pacific Time ) we called Key Bank together at XXXX. With her help of translating, I explained that I wanted to dispute all unauthorization transactions listed above, and that I urgently needed a provisional credit as in just few days my bills and rent were due. I said that my debit card is always with me and I have not given it to anyone physically or as data. The employee gave me a claim number for my case and said I just need to call the next day and ask for a new card. He explained that the bank would give me provisional credit for the unauthorized charges and that the deadline for concluding my claim was 90 days after which they will make the credit final depending on their findings. Both me and my friend said multiple times that I am disputing all XXXX charges and he said he got that. He also told me to call the bank during regular business hours to ask for a new debit card. The next day I called and ordered such a card, which I received a few days later and have been using it ever since. 
On XX/XX/XXXX, I received a letter in the mail from the bank informing me that I had been granted a provisional credit of {$220.00}. I assumed that the full credit would be made in installments, and that this was only the beginning, but by the end of XXXX nothing else had happened. Then on XX/XX/XXXX, at XXXX XXXX  ( Pacific time ) again with my friend, we called the bank with the question when to expect the rest of the provisional credits. The clerk explained that my case was still being processed, but he could not give details on whether and why the return of the sums was delayed. He advised me to wait until the deadline. After this conversation, a few days in a row, I received 3 letters in the mail. The first was dated XX/XX/XXXX, notifying me of additional {$1300.00} provisional credit ; the second dated XX/XX/XXXX, notifying of a provisional credit of {$290.00} and the last dated the same date - XX/XX/XXXX, of a provisional credit of {$590.00}. So far, a total of {$2400.00} has been refunded to my account. 
By the end of XXXX, nothing else had happened with the claim. So, I decided that instead of calling again on the phone, it would be better to go to the bank for a meeting in persona. I scheduled one online for XX/XX/XXXX at XXXX XXXX  in the Key Bank branch at : XXXX XXXX XXXX XXXX XXXX, OR XXXX. My friend also came with me, but she was not allowed in the branch due to restrictions connected to COVID-19 closures and distancing. I spoke personally with the branch manager. He explained to me that in cases of disputed charges the branches can not give information, and that this is possible to obtaining only by phone, calling their fraud department. And he offered that we make that call together. We called the bank fraud department and I asked why there was no development on my case for more than 3 weeks. I was told that they could not provide information, but that my case was still being processed. He advised me to allow the 90 days from the filing of my unauthorized use claim and call again only if not resolved. That's why I waited the full 90 days from XX/XX/XXXX to XX/XX/XXXX. I called again that day, XX/XX/XXXX as I never got any additional provisional credit to cover the rest of the disputed transactions. I asked for help from a translator in my native language. So, an interpreter joined the conversation. The clerk was unable to answer the question why I had not been credited for all the disputed amounts and called her supervisor for more information. The supervisor also did not say what the reasons were for not returning everything disputed to me, but only recommended that I follow each refund in detail, find which unauthorized transaction is refunded, and to re-appeal the amounts of the specific transactions that I believe have not been refunded/credited back to me. I explained to her that the information that the bank had given me in the letters ( tabularly on the back of each letter ) regarding the amounts recovered by it was not sufficient to specify the relevant unauthorized transaction, since so many of the transactions are repeating the same amount within the same day and they are all charged to XXXX, so no way to differentiate which particular one was credited back to me and which ones were not. The data in this table includes only Tran Date, Tran Amount and Merchant Name. And because I have multiple transactions with the same date, amount and Merchant Name ( XXXX ), I can not specify for which transaction they returned my money and for which they did not. But the supervisor did not offer me another option, except for a new claim. I asked her for a mailing address in case I decided to look for a more detailed way to explain the problem, and she gave it to me. ( XXXX XXXX XXXX XXXX, XXXX, NY, XXXX, Key bank, Customer Dispute ). She also told me that the bank had sent me a letter dated XXXX XX/XX/XXXX and that I would probably receive it soon. 
I received this letter the next day - XX/XX/XXXX. With it the bank notifies me of the following ( XXXX quote ) : As a result of our completed research, a credit of {$1300.00}, all or a portion of which previously posted to your account on XX/XX/XXXX as provisional credit, has been made final and is now considered permanent. 
This amount coincides with the amount from their letter of XX/XX/XXXX. They do not give me information on how the other amounts credited are final ( {$220.00}, {$290.00} and {$590.00} ). 
Then on XX/XX/XXXX I received 3 more letters from Key Bank for each of the remaining provisional credits becoming final, but there is no offered information why the total refund of {$2400.00} is less than the full disputed amount of {$4900.00}. I am still {$2400.00} short from the full total amount of unauthorized transactions, which is devastating to my financial situation, especially in the current COVID-19 situation. 
I had to find someone to help me translate this letter due to my not fully fluent English skills, thus the delay of couple days to request help from your office. 
Please help the bank to serve me in accordance with my rights and to refund all unauthorized transactions, specifically the missing {$2400.00} portion of the total unauthorized transactions on my account. 
Thank you so much for any assistance you can provide in this matter! 
If you have additional questions regarding my bank account information, identification and other details, or instructions and forms to fill out or any follow-up for me, please feel free to contact me ( preferably by email ). 
Thank you very much! 

Attached please find : * Copies of my bank account monthly statements, which I found online. 
* Copies of the bank letters regarding my claim/case and credits of unauthorized transactions.