Mersey Heating And Air Conditioning

For several years I've had my tankless hot water heater serviced (yearly) by Mersey and was always happy with their service. In November 2023 the hot water would go off and on in the shower so I called Mersey in a month before I normally had the servicing done - and the first thing their technician asked after opening the hot water heater was what company had done the last servicing. I asked why - and he said that they had left us with a dangerous situation - the external limit heat wrap (I believe this was the name) had not been put back into position. The technician had to tag and shut off the gas to the water heater as it had to be completely replaced as the excess heat had caused it to deform and it was leaking gas.
A Mersey sales person contacted me the next day and quoted me $16,000 for replacement - more than double what I ended up paying from a different company to have a combi-boiler installed.
I called Mersey multiple times over the next several weeks asking to speak to a manager. Every time I was told that a manager would call me back shortly. Nevermind that I was charged for the service call in which the gas was shut off to my house, really the least they could have done was call back to address the situation. I won't use Mersey again.