Hi Copper - this is a tough one, that's for sure.
I know how you feel about 'how can I be selling a 5-month old vehicle?", versus waiting indefinitely to the dealer to fix the liftgate. Does the liftgate not work at all? The key fob, the dashboard release AND the liftgate button all do not work? If so, that would be a TOTAL failure, not being able to access the rear cargo area!
Phew!!
This is a tough choice!!
What are you thinking?