This happened to me about 6+ Months ago w/ my CitiCard.
My Rate was 7.99%. I had a decent Balance on it. I got a thing in the mail saying it was gong to 24.99% on (whatever date). It also said, to opt out, call this number. So I did, and they opted me out of it. They said I can use the CC at the current Interest Rate until the expiration date on the Card.
The next week, they dropped my interest rate 1% to 6.99%. I have not yet received another intrest rate increase notice.
According to the new laws passed, they have to give you a 45 day notice.
I just recently closed out my CC with them all-together.
KillJoy