I purchased a cell phone and accessories, and received rebates to the original selling price in the form of rebate cards, rather than simply a refund check. The cards behave like credit cards, but come loaded with the rebate amount on them. My problem is, the cards expired before I used all of the value loaded onto them. When I contact the rebate company and the original equipment vendor, they tell me I'm out of luck. They will not extend the 'valid thru' date, nor will they issue me new cards. Do I have any recourse?