Mark 5 Spa Repair

He stayed open late so that I could get a transformer for my spa, so my first impression was that he was a good guy. He sold me the transformer off the books, cash, so that there was no tax. I thought, «cool.»
Replacing the transformer didn’t fix my issues, so I called him to inspect my hot tub. He came out and putzed with the electronics only to ultimately tell me nothing useful. He said it would cost more than the tub is worth to fix. He said the control panel was no good, the main board was fried, the heater didn’t work and was «leaking electricity into the water,» and that the pump sounded like it had marbles in it.
He charged $ 85 for his visit. I asked him if I could get $ 30 credit by returning the unused transformer. He refused, saying that he cannot accept returns of electrical equipment.
First of all, he sold it to me off the books, so yes he can!
Secondly, it was obviously a USED part he sold me, as he dug it out of a Tupperware container of used parts!
Ultimately, the only thing wrong with my spa is the pump only works on one speed. Everything else works perfectly!
I was screwed out of $ 115 for nothing.
Would highly recommend NOT calling this guy!