I had a similar problem with Greenwood Lake Sport Center back in the early '90's. That was before his FFL was revoked, but that is another story.
I bought a muzzleloader there. When I hunted with it and got caught in the rain the stock swelled up real bad. Althyough it was a cheap (made in Spain) rifle the guy there (Leo) told me it had the same warranty as a TC. So at the end of muzzleloader season I brought it there. When I didn't get it back for several months I kept checking never getting a straight answer. Finally I got him to tell me where he sent it. The importer was in Canada. They said they had the gun, but wouldn't release it because Leo owed them money on the original invoice from his purchase. Finally I got the gun back with a new stock, but it too lots of negotiating.