Snappy Electric Plumbling & HVAC Snappy Bill for a snappy ripoff price Marietta, Georgia

My past Property Management company hired Snappy Electric Plumbing & HVAC company to perform work on my Air condition unit in one of my rental properties.  Prior to my tenant moving in, another company by the name of Quality Home Improvement Heating and Air had diagnosed my AC and performed work on it.  The technician from Quality Home Heating stated that my AC unit may not last for a long time and I need a new replacement.  He went ahead and put freon in the unit and said it was temporary. When my new tenant moved in on June 1st, on the 6th she reported the AC unit to the Property Managment company stating the unit wasn't working.  The company summoned Snappy and the technician claimed that he put freon in the AC unit.  I later got a call from the tech stating that my AC unit must be replaced and it will cost me about $2200.  I told him that I would shop around and get back to him, which I did and I got Quality Home Improvement Heating & Air to  once again to replace the unit for $1350. I called the tech back at Snappy and told him that I am not going to authorize them to replace the unit and what was the cost of his visit?  He told me his visit would cost between $175 and $225.  I later received a bill for $304.25 for what was called an emergency call,diagnosis of local switch in OFF position, low on freon. Add freon by super heat, compressor with bad valves,slightly by passing freon and that the unit was fine at the time.
 When Quality Home Improvement Heating & Air went to replace the AC unit, the tech discovered that the compressor was shut and he said "the last technician could not have been able to tell if the unit needed freon if the compressor was shut." I later brought that discovery to my Property Management company who completely ignored my claims and refused to investigate it. QHI heating  & Air replaced my unit on June 9th 2010.
 I then received a second invoice from Snappy stating that they performed a diagnostic on the unit, not cooling properly,all gas levels normal,pulled and cleaned coil and this bill is for $338.75.  I called Snappy on November 9th 2010 and asked why were they called out since I had my own HVAC tech visiting my property on June 9th for AC unit replacement and June 10th to show the tenant on how to use the new unit so it can blow cool air.
The representative from the company asked me for a copy of my bill for Home Quality and the company's business number which I relayed.  The representative from Snappy spoke to the tech from Qulaity Home HVAC and after it has been explained to her, she called me back and said that the coils on the unit were not changed and I was still responsible for the charges.  I then called back the tech from Quality Home HVAC and he said he explained the work performed and there was no need for Snappy's tech to perform the work he claims he did because the coils were brand new.
 As I type this complaint, my issue has not been resolved and Snappy wants me to pay for false charges.