Legal Question in Credit and Debt Law in Massachusetts

You should certainly contact an attorney to discuss the circumstances of your situation in more detail. However, yes, generally credit cards can charge either the charge off interest rate (which is the default interest rate), the statutory rate of 12% depending on when or if they sue you, or at a bare minimum the 6% interest rate on cotracts that do no specify an interest rate amount. However, most credit card contracts do specify an amount. You should look at your card member agreement.

Yes, you are free not to use your credit cards anymore, but the credit card company is still going to charge interest on any balances that you still owe. After all, you still owe them that money.