Sometimes you have to do that. Back in the eighties I stayed with my original shop for about 3 years until they became a disorganized mess. Had to get my regs redone there after the annual service was fouled up, (reg free flow). After the second time I picked up my regs and made sure they were working properly on a tank at that shop, then walked out for the final time, and started going to another shop a few weeks later. That original shop bit the dust a couple years later.
The scuba training and equipment sales retail business is mostly mom and pop shops, but most of the governing certification agencies police them as best they can. Maybe you should consider contacting the issuing agency, and reporting the incident, (IE: Contact PADI, NAUI, SSI, IANTD, or whoever.) Was this by chance a PADI shop? (Euphemism for them is: Put Another Dollar In)