The tech who talked to me wasn't the guy who had done the other work. However, he was appropriately apologetic regarding the error his shop had made and took it upon himself to make it right. I will probably still buy stuff from them because they actually have some nice upgrade and replacement devices. It will get to the point that they dread seeing me because even though I pay cash on the spot (or at least, credit card...) they know I am savvy enough to catch them in bad things. And the only reason I don't do as much of that as I used to is that I'm tired of my knuckles getting all cut up on sharp edges.