When you turn your AC on, does it only blow air without the Cooling or Heating?
There may be a quick fix for it that will save you calling a technician.
Step-1 Outside near the compressor unit, turn the power OFF.
Step-2 Wait 30 minutes (This will allow the system to fully reset).
Step-3 Turn the power back on and try again operating the inside unit.
If it now cools, clever you.
Thanks go to Barry Mc. for the great tip.