Amex Credit Card Complaint

Amex Credit card department,

APR or interest rate California

I received an offer from American Express for a new credit card offering cash back after spending - and 0 % interest. I applied and received the credit card. I spent the money as detailed in the offer and received the cash back. American Express then changed the terms of interest and have been charging 24.9 % on the credit card balance. I did n't realize they had been charging me interest because my statements are electronic and I make the payments automatically. That is a dishonest practice and needs to be stopped.