I wouldn't worry either.. First because if you use paypal I higly doubt that you could open a claim stating that you rep does not work. You can only be refunded if you don't receive anything, which is the same thing you can do with your credit card issuers (Visa, MC, Amex etc..) Nothing less, nothing more. In addition you are their customer, so they are in your favour.
If you are afraid to get your credit card cloned or stolen, buy a prepaid credit card and recharge it only when needed, and your risk would be limited at the price you paid for the rep