I had almost the exact same experience with Bell Brothers about 8 years go.I live in an old home with boiler heat and ACs. I think Bell installed the boilers and the AC units some years ago before I bought the house, and I used them for a number of years for small stuff. This summer they came out when an AC unit went on the fritz, quoted about $1,000 to fix and also pitched a complete overhaul of the system.
Had another guy out, he said all you need is a new capacitor, it's a $20 part, I have one on my truck, and the AC was back up in 5 min for about $100.
Just one recent experience with Bell Brothers.
I had a regular forced air system, not boiler. During a regular tune up the tech told me the system "wouldn't turn on and had to be replaced".
Called another company and I don't remember what the issue was but it was extremely minor.
Told Bell Brothers I wasn't paying and disputed the charge on my credit card haha