Trane of Salt Lake City David Bills and Scott of Modern Heating and Air in Salt Lake City Made a promise of credit for part that failed, initially would not warranty a 15 month part Salt Lake City, Utah

On 13 May 2004 we purchased a Trane Furnace Model #TUY100r9V4W4, a Trane Condenser Model 4TTX4042A100AA, and Coil #TE366422505AP from Modern Heating Air Conditioning at 2578 W. Countryside Lane, West Jordan, UT 84084.  Scott Keller was our representative.
Trane was highly recommended to us for service and quality.  Other than two instances of plugged dranins everything worked fine until 14 October 2010 when the circuit board locked out (Trane XV90 circuit board).  Scott fixed this for $696.50.  On January 2012 the control board failed again after 15 months and new had to be purchased of $568.00.
We were disconcerted that the same expensive part had failed after such a short time. We repeatedly called David and Scott to have our furnace inspected to see if the part could be warrantied.  We even wrote to the Regional Manager, Stacey Hieb in Denver.

 Finally  near the end of March, David Bills called us and said that Trane was going to give us a credit for the part.  The credit however was going to be given to Modern Heating and Air which in turn would reimburse us when they received it.  Scott of Modern Heating @ Air said he would send the check as soon as he received the credit.
David Bills told us the credit had been sent but has given no written verification although requested many times.  Scott Keller will not answer our calls.

 Thus we have Trane promising a credit through their parts manager and the promise unfulfilled. We feel a company like Trane should stand by such an expense part for 15 months.  Why would they make promises of a credit and then not give it or verification of it?
Don't trust Trane!