Rear end dropped

A friend called to ask about a problem he had with his 96 E300.
The two bolts, that hold up the rear differential, stipped out while his wife was driving down the road. He had a friend tap the bolt holes up one size and put in new bolts so he could drive it to the dealership (100 miles). The dealership would not do any repairs under goodwill warranty, (80,000 miles on the car). They say it needs new bushings, 2 bolts, 4 wheel allignment, and 7 hours labor to repair. I felt the dealership should have taken care of the repair work under warranty since this is obviously a defect in design or workmanship, and is definately not a normal occurance for the differential to fall loose while some is driving. Has any one heard of a simular situation? Who can he call in Ga. to solve his problems with the repair work and or the safety issues of a possible design flaw?
Thanks...

[Benzmac]

Sorry, I doubt that it was a design flaw. I own a 210 and have worked on hundreds.

I wouldn't doubt if the differental was removed early on for a warranty repair such as leaks etc.... Then improperly re-installed.

This could explain the problem.