LAKES AREA HEATING & COOLING

Since the house was built less than a couple of years ago, the HVAC system have never heated/cooled the house to the set temperature. Our electric bill during the winter/summer months were exceptionally high but the temperature in the house never got to the setting we had it at. During peak times, the temperature in the house got worse!  We keep our house at 75 in the summer and 70 in the winter so it didn't make any sense. We've called Calvin several times to come and fix the problem, and he made some minor repairs and adjustments, to include adding freon because it was low. Our brand new system was low on freon after a few months of being in use. It didn't sound right to me. I asked him why that was and he explained that it came from the manufacturer that way and everything should be fine after he filled it with freon. I didn't pursue questioning from then because his explanation had already told me that either he's dishonest or isn't professional at his job. (Why didn't he filled it up when he installed our unit? Why didn't he checked for any leaks in the system?)  Our unit still haven't worked to standard and just recently, our AC stop blowing out cold air. I've called him several times and haven't gotten any response.