Bank of America Credit Card Complaint

Bank of America Credit card department,

Payoff process Oregon

I have a Bank of America Visa card. I had a balance of approximately $18000.00 at 16 % interest I used the remaining available credit for a balance transfer offer ( 18 months zero interest 4 % transaction fee ) Now the bank is telling me that my minimum monthly payment goes first to pay down the principal of the lowest interest. In fact my payment does not even go first to pay the interest I 'm being charged on the high interest balance, that interest is being added to my principal each month. This is a deceptive practice. Please help. Payments should be applied first to interest being charged on an account, then to the balance subject to the highest interest rate.