Let the body shop try again. If they get it right, great! And free! And if not, you simply have the same problem as now.
Suggestion: Go sit down with the body shop manager, make sure he/she understands the problem, and agree on your expectations and what constitutes success (e.g. "better" is not okay, "perfect" is okay). Have it clear in their mind too.
Bye bye E93 M3 - Hello F83 M4!