Discover Credit Card Offer of low interest without telling you that is a 6 or 12 months promotion and after that period will be 17 to 19% interest Los Angeles UT

Discover Card, with a FICO of 745 and paying on time since 2003. I called them to ask for a better interest rate and the person who helped me on the phone gave me a 3.99% interest what I think was grate and I accepted without knowing was a promotion for 12 months, but, the Discover employee never told me that information on the phone. After a year they started charging me 17.25%, this happen around 4 year ago, since than I have been asking for help without result until now that I stop paying. Now they are giving me 10%.

I think they Do the same trick to million of people making millions of dollars. What can you do to penalize this bank for cheating to honest people like me.

Thank you.