cupco plumbing

I hired Cupco Plumbing INC to fix a hot water issue in my bathroom shower ( Cold Water coming from Shower) . I research this on line and problem was likely a shower cartridge . Matt from Cupco explained the cartridge and shower valve that was connected to the cartridge was corroded and need to be replaced . He showed me green corrosion on the valve . Matt said a hole was needed to be cut out in the dry wall behind the shower to gain access to that valve to replace . I asked Matt what this was going to cost and he said $800 . I agreed to have the hole cut in the wall and shower valve and cartridge replaced . 20 minutes later he said I have more problems . He cut a hole in wall and installed 2 shutoff ball valves to the shower . He never removed the shower valve or furnish and installed a new domestic shower cartridge . He said he needed to come back at a later date and that I needed the valve , cartridge and single handle shower trim kit that was also damaged replaced . He said the bill was $1235 . I questioned why the bill was so high . He said he went above and beyond to try and clean that valve out so he didn't have to cut a hole in the wall . He said the valve was badly corroded and preventing water pressure . I told him I had good water pressure , just cold water . He said the valve was preventing hot water . I asked if there was going be any additional charges when he comes back and he said another $1000 to complete the job . Water was turned back on and he left . I called Chad from Cupco and told him I was overcharged, cancelling the call back and hiring another plumber . I hired another plumber and explained what happened . He said he has replaced numerous shower cartridges and there was always green corrosion on the valve . He said its normal oxidation . He turned off the water , removed the 2 shutoff ball valves in the wall . He said it was not code to have the shutoff valves in the wall . He replaced the shower cartridge only and reinstalled my existing shower single handle . Water back on with great pressure and hot water . He said the valve has nothing to do with hot water pressure . The cartridge does the mixing of hot / cold water . He charge me $300 . He told me Cupco was ripping me off . The valve was good and it did not need to be replaced. Cupco was using that green oxidation on the valve as part of there scam / scare tactics and now I have a hole in my wall that I needs to be fixed . So Cupco was trying to charge me at least $2235 for $300 JOB . They got my money , but if I prevent one person from steering clear of Cupco Plumbing . Its a victory .