Product: Credit card or prepaid card

Re : Account No. XXXX XXXX XXXX XXXX In XXXX of XXXX XXXX XXXX representatives approached us about a " whole house filtration system '' and offered 24 months with no interest if we would agree to use their credit card, have a representative come to our house, and present their offer. We did, and agreed to have the entire purchase amount of less than {$5000.00} put on an even monthly withdrawal amount to be paid off during the 24 months offered. The representative spoke with their credit department about our agreement and all I was asked was to say I agreed to have this amount spread evenly over the promotional term. This offer would only be available if one would agree to use their credit card and allow autopay, we were told, which I had opened in XXXX and maintained with zero balance ( {$0.00} ). 
We listed our property in XXXX of XXXX, received an offer in XXXX, and moved to another city shortly thereafter. We used the same servicing company who installed it to remove and store the system until we would be able to move into our new property by XXXX, when they came back and reinstalled it at the new house. With XXXX teenage children, while also caring for our elderly parents in Colorado, for which at least one of us had to travel on a monthly basis, while trying to settle in we noticed continuing ongoing payments to Home Depot. This came as a surprise since it was past the 24 months during which we had agreed to have it paid off completely. 
We contacted them and were provided with false information each time such as " this account did not qualify for the zero interest '', " you did not pay the account off, therefore it became disqualified '', " we mailed you notices and statements '', " you agreed to terms when you opened the account for the purpose of purchasing this system '', etc. none of which were accurate. In fact, we never were notified of such a high interest rate being applied, and even worse, found out that the interest was backdated to the beginning, going forward. 
We notified them of our agreement to have even amounts taken through 24 months to pay off the account since this was the only way to get the promotional deal, that we were not given the opportunity to pay for it in full at the time of purchase, instead of financing, the fact they never sent any statements, nor any notices about the balance not having been paid off, or that they had decided to take a lesser amount than what was agreed to by us which would have paid off the entire amount before the promotional period would have ended. 
Not only they did mislead and misrepresent, they also backdated the extremely high interest rate to the entire beginning balance, to the tune of 25.99 %, and started compounding interest on top of interest, which we believe is also against the law. 
In total, they collected almost {$7000.00} in interest and told us we owe them more than what the initial purchase was at the beginning. We now know they charged {$3900.00} in interest during the initial 24 months alone. 
Since their website only allows you to go back for a few months, it is impossible to get information, statements, documents, etc. We have spoken with numerous representatives during multiple calls, requesting information, statements, or other pertaining documents. Each tells us the same, which is their system can not go back further than a few months to a year. They are not even able to provide us with the total interest amount they have charged during XXXX. We have asked, but not received copies of our statements which we have never received before. 
We also have repeatedly tried to solve this with numerous of their departments, through Citibank, with whom we have other cards in good standing that are on autopay for the entire statement balance on a monthly basis, with Home Depot credit services, even with their " Executive Response Unit '' where we had the pleasure of speaking with " XXXX '' who said he was a " direct report '' of Citi 's CEO, " XXXX XXXX '', and while faced with arrogance and attitude, were told by him to " do whatever you'd like '' when we let either of them know we would not be left with any other options but to file a formal complaint. 
In addition, we left two voicemails for another executive we were given the name of, " XXXX XXXX '' from the Executive Office without ever receiving a callback. We'd be glad to provide you the direct number for her if needed. 
When speaking with their representatives, we offered to pay a reasonable amount of interest if we have to, and close the account, but asked that Home Depot would take responsibility for their false actions of : 1. not making accurate arrangements as agreed by us to have the entire amount be paid off during the promotional zero interest period, 2. due to our agreement in item # 1, notify us of an unpaid balance at the end of the promotional period, 3. provide us with monthly statements, 4. provide us with notice to increase the rate from zero ( 0 % ) to 25.99 %, 5. to provide us with end of year interest payment notices, 6. to backtrack and charge the extremely high interest rate on the entire balance from day one, 7. to compound interest on interest, 8. to not change our address on the record, despite numerous notices and occasions. 
It is noteworthy to mention we also have an active " Pro Desk '' account at XXXX XXXX and that is how we found out they maintained our old address from 5 years ago while we lived in Colorado, not where they installed the water filtration system in California for which they set up the " promotional offer '', which they also were notified and made aware that we moved out of in XXXX ; sent their representatives to move the system from, to another house, in different cities. 
We have repeatedly requested corrections be made to our address as well as phone numbers without any success. 
We are concerned about this damaging our good credit. As well, we have repeatedly tried to communicate the type of hardship they are putting our family through during these unprecedented times without success.We are concerned about the fact neither us, nor their representatives are able to view or obtain any of this information in their system. 
Citi should be able to review our other accounts and realize the huge difference between this account and our others, and realize the lack of good faith provided by Home Depot representatives.