Vw Phaeton trunk does not open and shows in bc that the flap is open what to do?

Vw Phaeton boot doesn’t open and shows in bc that the flap is on what to do? Does not react on pushbutton, not on remote control, does not open with key, keys can not even be turned to the right, no milimeter!!! According to VW workshop you can only open the trunk if you expand the complete back bench and then unlock the lock from inside and cost at least 2 working days….For me actually incredible, there must be a possibility to open the BC and reset the wrong message??? Who knows this problem and what solutions there are, and prefers solutions that do not cost 2 days… Thank you in advance