Bait and switch Groupon deal. This merchant decided on their own to refuse Groupon deals and has left it up to each customer to "deal with" Groupon in trying to get a refund.
Groupon knows nothing about this contractual break and as such is not freely giving refunds.
A significant inconvenience. If this merchant can't keep it's agreements, how can a customer trust them to be honorable or trustworthy in any other care of treatment, deals, etc.