Man o man, tough night!....I was going to tall you to trip the breaker by the outside unit and run strips. The installer could have wired it wrong or installed the old strip that has since failed, or just did not install a strip or wrong specs. I had a 5 ton heat pump that lasted about 12 plus years, but decided on a straight cool and strip heat over the heat pump because we rarely get the bad cold further south than Interstate 4. I'm guessing they high pressure nitrogen purge the system if it's r-22[leak check] and recharge you, check, replace wiring and strips. Ask the AC guy if the air handler is the proper size for the outside unit and if the wiring is correct. Also request that he check your thermostat for a "swing" feature so it's not cycling on and off for one degree temp changes[honeywell is the worst for this]. The swing feature allows longer unit runs, is easier on the compressor, and saves you power because of repetitive power spikes to start the system too much per hour.