Bank of America Credit Card Complaint

Bank of America Credit card department,

Payoff process New York

I have a credit card with Bank of America. I have had this card for quite some time and there are multiple balances with difference interest rates on this card. I thought if I made a monthly payment that is higher than my minimum payment due then that extra amount would be applied to the balance with highest interest rate first. But they are not doing this and I asked about it and was told that this is not how they distribute the extra amount that is paid over the minimum due. But I thought this was a regulation in the CARD Act. Am I misinterpreting the law?