...... on the first pedal stroke after it was serviced(and new chain) the chain snapped and ripped out my front derailleur and destroyed my frame . I'm fuming .
At a guess, I'd say the quick link wasn't engaged properly on both sides. The fact that the chain wasn't wasn't even sized points to a bit of a rush job.
When I fit a new chain (three in the last year), I run my eyes over every link looking for obvious defects. I've never yet found any, but you never know. Also, I take it steady for the first mile or so on a new chain (easy gears, no uphill stuff).
I'm sure the vast majority of bike mechanics are diligent but there are bound to be some who are having an off day who maybe, are not as thorough as they should be.
Personally, I'd rather do all of the mechanics myself. I might take ten times longer than a shop mechanic to do the same job, but I check and check again because it's me who's going to be risking his his own life by riding the thing afterwards. There is so much good information on the web that bike repair is no longer the mystery that it was 20 or so years ago. Once you've done a particular job once, the second time is easy.
As for the liability issue, he is running a business trading a service for money and his service fell short. Your only problem is going to be proving that his actions actually led to the chain failure.
Good luck.
