300E bent valve new heads what to do???

[JAlex]

Ok heres the deal. 89 300E 197,000 miles. I took it to a small shop that specializes in german cars, for a head job. The were having problems with their machine shop and didn't have a good place to reccomend so I researched and found out where the biggest mercedez dealer in north Los Angeles County that does ALL of the benz head work. So I get a call from the mechanic today stating that they had to remove the just rebuilt head due to a bent intake valve on the # 6 cylinder. They say its the machine shops fault. First words out of my mouth are "the timing must have been set wrong" of coarse they claim it was correct and the machine shop botched the job. Of coarse we all know what the machine shop is going to say!!!
So two questions.
1. What things can contribute to a single bent intake valve??
Do you think its the machine shop doing a bad job or the mechanics screwed up something??
2. Can they reuse the head gasket, exhaust gaskets and intake gaskets(I think when they ran the engine it never got warmed up).
Thanks in advance.
Alex