Confusing or misleading advertising or marketing: Debt or credit management

I was pay off $14000.00 And my balance is $2700.00 left That principal $17000.00 They send me a fee of $8200.00 So when i call them My balance is wrong and they tell me You should be pay off total amount if $17000.00 But you didnt pay So we are adding the fee but i said I believe this is no any interest change They say no not for 2year after Well i didnt know that They say your card is promotion card But i didnt open the card Bank and dental office have a some kind of deal So i didnt know all that Dental office lady didnt explain all that Only i know is this card is no interest until pay off