Can i go to jail for default on my credit card.

credit card comp. changed my intrest rate even though i am not over the limit or late

As long as you didn't commit a crime (such as fraud) to obtain credit, probably not. Even if you continued to use the card after knowing you would be unable to repay and would eventually delcare bankruptcy, you won't go to jail. It may be that the Bankruptcy court will order that the purchases made after you knew bankruptcy was in the offing be repaid, and not set aside by the bankruptcy. We don't imprison people in this country for minor offenses unless they are related to marijuana.