We built our home in Cleveland, GA in 2017 while living in MS taking care of my 92 year old mother-in-law who had advanced Alzheimer's, and her husband who was legally blind.I had two Trane HVAC units installed in our new home. One unit was not properly installed. As a result, there were, and still are, significant air leaks where the middle front access panel connects to the unit. I called my builder and explained the problem. He called Installation Management Services (IMS), the original installer, but IMS did not show up. After a few more call, IMS did show up. IMS checked the air leaks, but told me the only solution was to put sealing tape around the seams where the panel connects. I called my builder again; however it took a few more calls to get IMS to respond. The results were the same.Next, I called Trane Customer Service (CS) and explained the problem. I provided them with the serial numbers of the units, but the CS agent could not find where they were registered. I talked with my builder who assured me he had registered the units, I called Trane again, but this time the CS agent did find where the units were registered, but in my builder's name. Again, my phones calls produced to results.Next, I wrote the president of Trane, Mr. James Bingham. Trane never forwarded my letter to anyone in Trane. Instead, Trane sent it back to CS, the company that had been unresponsive. I called CS once more. This time the issue was elevated to a Resolution Specialist. That person contacted IMS, the original installer. The Specialist, while trying to help, produced no results. I then asked the Specialists in Trane to whom I could elevate. She told me there was no one, and that she was as high as the issue would go. She then closed the issue.I am now left with one unit that still has air leaks resulting in heating and air conditioning a storage area that does not require temperature control. Trane's contracted CS company has been little help, I cannot find a contact within Trane to talk with, and the original installer has been more hindrance that help.Anyone have any suggestions?