B-N-K Plumbing

I have a home warranty service. The first time my tub wasn't draining. The used a snake, ruined the glazing on our cast iron tub. & then they said the main sewer pipe was plugged & had to have a wall busted out for repair. This made no sense as all the other 7 drains in the house worked perfectly. A union plumber website suggested filling our bathroom sink & with the pressure from hi to low, the obstruction would most likely pop out. Presto. BNK costed us $1000 to reglaze the tub & lost our deductible to them through the warranty company. Had to call warranty company again as the hot water for second floor was foul rotten egg smelling. We have 2 hot water heaters. 1 tank for each floor. Quick Google of the Plumber Association said simple fix though plumber needed. A different plumber came out from BNK per my request. This guy said he never heard of an anode rod (The hot water heater was replaced in 2019) plus he never heard of the option of putting bleach in the tank to kill off bacteria. His final report? We had water quality issues so it was not fixable? I suggested that common sense would suggest the water quality could not be the issue because the cold water on both floors plus the hot water on the first floor had no odors & we only had 1 city supplied water main coming into the 2 flat. I would never recommend them. They apparently have no clue to the basics of plumbing.