Same thing happened to us. We purchased a new home, and haven't liquidated the old one yet Credit report went from 802 to 780 not like it even dropped out of excellent, we haven't missed any payments have paid ahead but the interest on card jumped from 9 to 21%. We opted to pay off the card and to cease doing all business with BOA, but that may not be an option for everyone. This kind of predatory lending seems to be a pattern with certain lenders of which BOA is one, and it has significantly increased profits for shareholds.
There are two things you might consider.
Option 1. Buy a share of stock, you can even charge it to your card, as a shareholder you can attend the sharehold meetings, which means you will have to attend this meeting to effect any changes, large shareholds rarely attend meetings they send in proxys however shareholds have the power set or reject policies, if all card and mortgage holders were also shareholds they could band together to change any policy.
However if you are waiting for the good fairy to come along and wave her magic wand you might want to opt for option 2.
2. Write your congressman and support and vote for the guy that actually doses something about this. There was a bill introduced by Sen Dodd, D Banking (the one running for president), about actually setting rules for predatory lenders, however it has been my observation there can be unintended side affects to this sort of legislation.
I actually did both so see you at the next sharehold meeting.
All the best,