If your outdoor unit compressor does stay on after the thermostat is satisfied your indoor blower should shut down , if that is happening that is not a good situation as the indoor coil is the condenser and your head pressure would increase and depending on the breaker size should trip as the pressures rise amperage rise also or if this unit has a high pressure switch it should trip . You do not mention if you run the fan in the ON position to keep the pressures normal. How do you know if the compressor is actually running after the heat satisfy and only the outdoor fan is only running. I would call for service again rather quickly and run emergency heat ,if your t-stat has that feature.