Product: Credit card or prepaid card

I entered a contract with XXXX XXXX for home remodeling in XX/XX/XXXX. The work totaled roughly {$100000.00}. After 8 months ( XX/XX/XXXX ), XXXX XXXX did not finish the work. The work they had done was defective and did not pass city inspection. XXXX XXXX walked off the job and abandoned the project without fixing the defective work or completing the job. I filed a dispute with 3 credit card companies as well as with XXXX XXXX. After 8 months ( XX/XX/XXXX ), we finally settled and part of the settlement included my not rescinding the dispute on any of the credit cards, and that I would not owe the amount charged to those cards. 2 of the 3 cards complied with this and never required me to pay off those cards. However, the XXXX XXXX store card ( under Synchrony ) did not comply. We assumed they had, as we received no demand for payment until XXXX of XXXX, where they demanded repayment of roughly {$35000.00}, and they added interest of over {$9000.00}. When the card was opened, there was a 2 year, no interest term on the account. 

If Synchrony felt that this dispute was resolved in XXXX   favor when we reached agreement with XXXX in XXXX of XXXX, why didnt Synchrony send me a letter and billing then that showed that Synchrony did not find the dispute in my favor and required payment. At that time, I had a 2 year 0 interest term on my Synchrony card. Synchrony did not get in touch with me until XX/XX/XXXX to notify me that they felt I owed this money, plus over {$9000.00} in interest that had accumulated over nearly 2 years since the dispute resolution. Why did Synchrony wait so long to notify me that they believed I owed this money? Why was I never informed that interest was accruing? This is required by law under the Fair Credit Billing Act ( FCBA ) to be provided for each billing period in which a customer owes more than one dollar or on which they have been charged a finance charge. They are required to resolve the dispute within two billing cycles ( but not more than 90 days ) after getting my initial letter in XX/XX/XXXX.  If Sychrony had determined that I owed any or all of the disputed amount, they were required to send me a written explanation in the required time frame. Synchrony did not do that. What it did was to send notice out of the blue nearly 2 years after the dispute ended stating that the balance was due, plus nearly 2 years of interest. The FCBA also states that any creditor who fails to follow the settlement procedure may not collect the amount in dispute, or any related finance charges, up to {$50.00}, even if the bill turns out to be correct. 

Furthermore, my credit reports shown a {$0.00} balance on this account for the past 2 years. 

I opened a new dispute with the XXXX XXXX card, providing them with the written evidence from XXXX XXXX that states we will not be required to rescind the original credit card disputes or pay those balances, but the XXXX XXXX   card/Synchrony, still refuses to honor that and insists on charging me the balance plus interest. 

I appreciate your help in making sure this final mistake is cleared up immediately and to recognize the binding legality of the email agreement with XXXX regarding these charges with Synchrony. We do not owe any money to the XXXX   credit card.