AC Shutting off and then running for 16 hrs straight no problems. Then shuts off and will not restart.

Contractor came out and tried to fix after blowing 10 fuses and trying to sell a 500.00 thermostat to me saying this was the problem. Then throws up his hands and says I don’t know will have to send someone else out to repair.
Contacts do not have 24 volts when checked. Second company came out and found theproblem while doing basic continuity check what did they find.