oemcaraudio Defective Repair Burnsville Minnesota

I'm the sales manager at a Chevrolet Store in Montana.  The dealership sold a used Suburban 2 days later the customer comes to the store to explain the DVD play stopped working.  We agreed to repair the unit.  The head is removed we sent it to oemcaraudio for repair.  The unit arrives back at the dealership, we install it back in the Suburban.  The DVD still doe not play on the on the rear seat screens.  After repeated attemps for assitance from oemcaraudio the unit still does not work.  GM tech support told us twice the repaired head is defective.  The head had no output signal.  19 days sine the unit arrived back at the dealership have gone by and we decide to purchase a GM factory rebuilt head which requires a core return of the defective head.  The GM rebuilt head arrives and everything works fine. 

Now oencaraudio wants us to return the defective head to them so they can remove the parts they claim to have installed.  It is not their head and we sent the head back to GM when we ordered the rebuilt one.  Now oemcaraudio is refusing a refund. The cistomer service was very poor and emails over the ebay system took days to be acknowledgeed.  $320 for nothing.  ebay offers no support since we dd not return the defective unit.  ebay and oemcaraudio just lost our future business.