restaurant.com Coupon not accepted; no refund Internet

I used restaurant.com to purchase a discounted voucher for a local restaurant.

The restaurant denied any relation to restaurant.com. There was a phone number on the voucher, specifically labeled for the restaurant to call with any questions. The manager did so, but the phone was not answered.

I contacted restaurant.com the following day. According to them, the voucher was redeemed. Evidently, as soon as someone phones that number on the voucher, it is "redeemed" and no longer useable. They did not respond at all about the restaurant not participating in their program.

I am very dissatisfied with what I see as a scam.