I can see the principle behind having Bmw resolve this it just seems alittle excessive to want to get rid of the car cause of a damaged rear bumper insert. Its a $200 part and even with paint wouldn't cost more than $500. Thats not enough money to cost you this much time and grief.
I would have fixed it on my own and send the bill to BMW for reimbursement.
Current - 2013 N55 535xi Msport SAT
Retired - 2009 N54 335i Msport 6MT
Retired - 2000 M52TU 323i ASA Supercharged 5MT
More Photos of my car here