The precise charge will depend on large part on how much you stole, since charges (and jail time) for the various "theft" crimes increase with the size of the theft. Depending on the amount, you could easily be faced with felony theft charges. You could potentially also be separately charged with "identify theft" if your state has criminalized that, since in using another's card, you passed yourself off as him or her; and you might also be charged with fraud (committing fraud vs. the merchants who accepted the card, for example). If you stole the card from a mail box, additional charges, pertaining to theft from the postal system and interference with the mail, could apply. You will also be in violation of your probation.If you have not yet already, consult with a criminal defense attorney IMMEDIATELY. Remember that  you have an absolute right to one, so if you can't afford one, one will be  appointed for you.