Have you tried being a bit of an asshole back? I don’t mean just being rude, but familiar like in the way that their friends might give them grief in a joking way, without all the typical customer service framing.

My work moved a store from a small city to a small town once and there was a bit of a cultural difference between the locations. I could swear at my clients and say things that would have gotten me complaints from in the city, but at the new location, everyone loved it. If I treated them with the typical sort of customer service the people in the city preferred, it came off as fake. They wanted “genuine” people (not actually genuine, just the appearance of feeling of it, which is why I say it was cultural). Most of our clients were long-haul truckers, ranchers/farmers, and mill workers.

I don’t come off as a tough guy or particularly masculine at all, I just started responding to their crap with half-joking grief and eventually learned it was better to just dish some out from the beginning. Swearing also helped a lot.

I don’t know the specifics of your work and it could be a completely different situation, but maybe there is something about this location that is different from the other stores and approaching your clients differently would help ease the pressure? Likewise, maybe they’re just assholes for some reason.