I live in a two story house I have two units couple of days ago I had my units serviced the tech guy cleaned the coils and added more freon to the upstair unit also he changed my thermostat for the upstair unit .since then upstairs is very hot the ac does not stay on it turns on for a couple of minutes and it turns off .the thermostat unit works fine is cool down stairs.please advice what to do.

Call the tech back. Anything done is under warranty, or should be, read your work slip or invoice.

Going to ask that this get moved to HVAC form.

If what you've said so far is all that has been done to your units and everything was working fine until the tech worked on your units... he was there to only make money. Its sad that our trade has turned into nothing but greedy, unskilled, a--h---s.

Call them back and tell them you want your old stat back for starters and then ask this tech what your superheat was (should be as close to 15 degs as possible) to warrant the extra gas. What most people don't understand is a air conditioning system is a sealed unit and should never have to have gas added This is a scheme used by the bumbs out there to pray on the public. If gas is necessary the unit needs to be check for a leak and the leak repaired. Find a better company to do business with.