Here are a few things that you should do before calling an HVAC company for repairs:
Ensure that annual maintenance is being carried out regularly.
Change the air filters if they are dirty. It is very easy to change them, and you can take care of it yourself.
Make sure that all your doors and windows are properly sealed.
Clear the area around the compressor unit and see to it that there are no obstructions.
See to it that your family members or visiting friends have not made any changes to the thermostat.