£6.3k bill - Charging issues after CCS upgrade - 2017 Model S

[Irelandowner]

Hi Folks, I paid Tesla for CCS upgrade it worked for first charge, and then on second I wasn't able to charge at home using a type 2. Telsa pushed me to get a KIT,SERVICE,GEN3 CHRG SYS,72A,3PH (1035647-01-E) saying this would fix it. £2.5k spent and issue has got worse, now car not charging at all by any means Inc CCS. They want to charge me to replace the kit again saying my home charger blew up the charging kit onboard the car, but 2 certified electricians have tested with one even charge his own model 3 and saying it's not the wall chargers issue. They also want to replace the charging port as the pins doesn't have the plastic protection around it saying that's what caused the problem total quote £3.8k on top of initial 2.5k. I bought the car private second hand. Hand it for a month with no charging issues, and never even realised plastic surround was missing. Any advice please?