Giovanni's Pizza & Pasta

We went to this restaurant for lunch after purchasing a restaurant.com voucher. We knew that to use our discounted voucher we had to spend $35 which was fine. Actually, the order we placed totaled more than $35 and we do tip generously. We received our drinks and then is when the trouble began. Our waitress who btw was VERY NICE, said she had to check and make sure they could take the voucher. She returned saying that Giovanni's would NOT accept the voucher. She also stated that customers had come in the night before to use the voucher and were told that they could not use this. She also stated there was not a manager on site and she also stated they had said they needed to put a sign in the window stating the voucher was not valid. She stated restaurant.com had signed their restaurant up without their knowledge. They offered us nothing for our troubles. Now mind you, we had put in our food order already, so we feel sure it was cooking. We paid for the drinks we ordered and left. I left my phone # for a manager to call me, as I thought this was poor customer service. That was 24 hours ago, no phone call and restaurant.com is still selling these vouchers. My question would be if a manager knew from the night before that this was issue, why was their no sign in the window. This is false advertising and I doublt seriously restaurant.com would have signed this establishment up without their permission. Giovannis has lost good customers over their lack of concern with this issue.