Sorry about your experience OP and I hope they get everything fix up. I heard Rallye BMW is a good place to do service and Dennis the SA drive a M3 as well.
I am planning to bring my car there for my 1200 service. If you looking to switch try Rallye BMW. Here is the link with all the good remarks.
http://www.m3post.com/forums/showthread.php?t=672868