My guess is that he had the wrong kit. There are two different kits, one for older, i.e. Gen 3 ECU, vehicles, and one for newer, Gen4 ECU, vehicles.I had a Tesla technician out today to retrofit my early 2020 Model 3. It was the first one that he had done.
Unfortunately, it didn't work. He tried for a couple of hours. He said he would work with others to try and get it sorted out.
I don't think there should be any labor charge, the retrofit price includes everything. (ECU, CCS Adapter, and installation)The estimate was $475 + $126 labour (0.6 labour hours). The $475 appears to be for the hardware itself.