Product: Money transfer, virtual currency, or money service

I am a sole proprietor. My client preferred to use XXXX for his transactions of payment of invoices. This method had worked for several months. On XX/XX/XXXX I had submitted via email two invoices that just so happened to equal the same amount for this month, both were for {$720.00} On XX/XX/XXXX I accidentally sent the client {$720.00} when I was first using XXXX rather than requesting it. I was rushing through the transaction and immediately discovered my mistake upon its completion. I immediately contacted my PNC bank and requested the funds be returned because I could not find the cancel transaction button on XXXX. I later learned that you can cancel a Request for Money through XXXX, but you can not cancel the Send Money transactions. This is crazy to me. PNC said that this would need to be done peer to peer and that they could not reverse the transaction. Another mystery I do not understand. I can stop almost every transaction that I do but this one. 
My client was not immediately available, but I sent a second transaction through XXXX with the memo to my client of what had taken place. I said in the memo of the XXXX transaction, " please send back the funds I accidentally sent to you. '' When I later spoke to my client he was understanding of the accident and joked that he was glad that " he didn't make the mistake. '' He checked his accounts and said that it had not gone through either account. He even sent me a screenshot of his account activity for that day. It did not show the supposed XXXX deposit that XXXX documented. He paid both invoices on that date fo {$720.00} each. I told him that I would check back with him the next day in case it took some time for that money to come into his account. 

When I checked with him the next day, he told me that the transaction had not gone through I continued to check back and forth with him through the XXXX when I decided to enter a dispute with PNC Bank. This met with great confusion by every associate that I spoke with since the payments for my invoices were for the same amount as the money I sent to my client. They would tell me, " well on the twentieth he returned the money to you. '' I said " no, you don't understand, I had two invoices for {$720.00}. He paid both of those invoices, but because he says that he never received the money into his account, he was not going to send the {$720.00}, I sent him {$720.00} accidentally and two invoices totaling {$720.00} each. He paid the invoices, but the {$720.00} has not been sent back and he said it never reached his bank. '' The associate said that they would enter the dispute and said that if the XXXX transaction was not claimed within 14 days, the money would be returned to my account. 
This lasted approximately 18 more days, I continued to call to assess the progress but there was not progress and the XXXX transaction of {$720.00} had not been returned to my account. They said that they would continue to research the dispute. 
On XX/XX/XXXX PNC placed {$720.00} into my account and listed it as provisional pending the conclusion of their investigation. On XX/XX/XXXX, they pulled the {$720.00} provisional funds from my account and claimed that the dispute was denied. They claimed that the transaction was processed as instructed and therefore the money would not be returned to my account. 
I contacted my client and advised him that PNC Bank was claiming that he had received the funds despite his insistence that he had not, and that they were denying my dispute. He immediately sent me an emailed copy of his bank account statement for that time period that showed no deposit from XXXX to his account. 
I requested that PNC Bank send me all of their investigation into the activity so that I could see what their investigation had shown. They said that they would send that to me in a letter and it would take XXXX business days. That letter dated XX/XX/XXXX arrived on XX/XX/XXXX and basically said the exact same thing that their previous letter to me said that my dispute was denied. In that same letter, it states that I have a right to request the documentation we relied on in making our decision. 
On Tuesday, XX/XX/2020, the day after memorial day, I contacted PNC Bank and spoke with an associate named XXXX. She advised that they had no documentation to provide to me. I questioned that if they had no documentation to provide to me, how did they come to the conclusion that the dispute should be denied. She said that XXXX transactions were final and that this was the final answer. 
In my opinion, No Investigation really took place.