Bank of America the sub-prime credit card company

So, a couple of month ago, BoA sent a notice in their cc statement stating that they were going to increase my APR without any justification. I mean really, I have never been late on any payment, on any account, ever! I have a FICO score of 776! So I quickly paid them off. I then called and asked why the increase? they said that I carried a balance two months ago and again a year ago. I am not sure what they think a credit card is for, but I paid it off anyway. So I called today and was told the same thing. I asked why, and was told that they were not going to argue with me.

oh well, yet another credit card for the sock drawer.