WA/Restaurant.com sold me invalid? gift certificate

Tonight I purchased a $25.00 gift certificate through Restaurant.com for $10.00 to be used at The Village Inn, here in town . The deal was I must purchase a minimum of $35.00 to redeem the $25.00 gift certificate, which my husband and I did. When my husband and I went to pay using the gift certificate the cashier stated ' "We don't take these gift certificates any longer." ' Shocked and confused, I asked what was going on here and why not, I just completed a transaction on line with Restaurant.com, they took my money. The cashier stated that the gift certificate was valid under the 'old' management, that they are under 'new' management now and that the new management have tried several times to get Restaurant.com to take the 'offer' (gift certificate) off their web site, but they have not done so. I ended up paying for my meal in full, without getting to use the gift certificate I purchased, because The Village Inn (cashier) would not honor it. Who is at fault here, and what can be done legally, if anything? - J.F. in Wa. state