2007 Factory remote start errors

We have a 2007 Yukon with remote start installed from the factory. Randomly with no pattern you start it with the remote and it will startup and shut off right away. Then it progressed to not starting at all via key or remote. So we sent it in and they installed a "resistor" as they called it in the high speed communication wire. I was a technition up until a few years ago and still do a lot of work on GM vehicles. i know the service support from GM to the technitions is poor at times. We dropped it off today and the tech who had been working on it stated Techline most likely won't allow him to do anything due to the fact that the problem is intermittent. I paid 40,000 for this pos and am real mad over this information. The question is does any one else have this problem or has anyone solved this problem before on the 07 Yukons?