Similar thing happened to me once many years ago in Musical Exchanges in Brum, though not with regards to a setup. I’d gone in to pick up a Jaydee GA24 I’d reserved and there was an issue with the pickup selector. Instead of taking it to the repair guys the salesman took it upon himself to “fix” it and the electrics went off completely. After spending some considerable time trying to fix it, he gave up and took it to the repair section and was summoned by the manager, who bollocked him. In the meantime Id tried another Jaydee Supernatural and decided to go home with that instead, so it worked out ok for them. Unfortunately the one I bought proved to have an iffy neck that would never settle, but by the time I’d worked that out it was too late to take it back. I wish I’d stuck out for the first one, but I was really annoyed at the time, having had a 3 hour train journey down, and didn’t want to have to go home with nothing.