My wife and I opened a consumer credit account with Home Depot/Citibank in XX/XX/XXXX to finance the purchase of a new roof. We were informed at the time that the financing would be at 0 % interest for XXXX months and if we paid the balance in full prior to the end of the XXXX months we would not pay any interest. When we received our XX/XX/XXXX statement we realized that the 0 % financing was scheduled to expire in XX/XX/XXXX after only XXXX months and at that point we would be charged interest retroactively. We contacted customer service and were informed that they would extend the 0 % financing for the full XXXX months. When we received our XX/XX/XXXX statement we observed that the 0 % interest had expired and that interest had been applied retroactively raising our monthly payment from approximately {$100.00} per month to approximately $ XXXX monthly. We again contacted customer service and were told to make our originally scheduled payment and that the 0 % financing would be applied retroactively. In XX/XX/XXXX I began receiving collection phone calls and when I viewed the statement online I realized the 0 % financing had still not been applied. I contacted customer service and was informed by XXXX in Escalations that the 0 % financing had not been applied because there was an error in the original account notation in XXXX. They said they would apply the 0 % financing retroactively again as soon as I made the account up to date and paid a past due {$210.00}. I informed them that this was unacceptable as the account was already up to date per the original 0 % financing offer and that I would not pay {$210.00} in interest due to their error. They said that the amount would be applied retroactively to the principal as soon as the account was up to date. I have no faith in that promise based upon the interactions over the previous XXXX months. 
