So go to your bank and report that you didn't make these purchases. They will cancel the payments and probably even investigate it if you tell them about this fraud. You can also get a replacement debit card with a new number on it.
Listen, all you have to do is call your bank, make a report that your information is stolen, list off the fradulent transactions, and they will block your card and send you a new one. Takes about a week. Then you should try and contact the merchants involved to try and get some of that money back. It helps to file a police report as well.
I had this happen to me not long ago. It's an easy fix, but it's a pain having to update your information with all those you do business with. Do you pay for gas at the pump? I think that's what happens in a lot of these cases.
Jews go round robbing on these matters too. At least, I have personally experienced this going back and forth going 99.9% of times unsuccessfully.
Regardless, if you put your card online, be careful. I would advise against using the same PC for purchases that you use to be around here or in other 'questionable' sites that (((Some))) people may not like.