We're considering our options at this point, but chargebacks will hit us NOW. Filing charges against GAW means we get in line to collect "anything" which won't be much when it's all said and done.
If I were in your shoes (I wouldn't be, since would never have repped a questionable operation, but just for the sake of argument) I would be trying 1000% to find a way to make my customers happy, or not happy at least less pissed off. If I go to Home Depot and buy a box of wingnuts, and find when I get home that the box is empty ... Home Depot is going to refund my money even if they paid for the empty box with cash. This is not any different.
I am not your customer, but you might consider store credits, a special deal on something else, etc. so you at the very least are sharing in the pain and making a customer a deal at the same time. FWIW.