Mitsubishi Repair: Mitsubishi Glant 2nd Timing within 9 months ?, worst case scenario, interference engine

Question
I have a 2000 Mitsubishi Glant model ES 2.4L with 138,0000 miles on it in Sept 2005 then my timing belt went, the engine was not "a crash engine"
(Lucky) I had it replaced with, Timing Belt with tensioner, Balance Shaft, Crank sensor, Crankshaft Blade, $600.00 later all went well.
Now 9 months later the Timing belt went again driven 13,000.00 not so lucky this time the engine was leak tested and found out to have bend valves with engine damage. SO a 6 year old car is now gone. I would like to know how can this be? As of right now the car has not been touched there was a new inner tensioner replaced back in sept, Who is at fault I'm not!! is it the original auto mechanics, or defective parts? the engine was not broken down yet this just happen two days ago. I cant see myself buying a new car!!.  where do i go from here need direction  

Answer
Mark,
If you had the dealership replace the timing belt, take it back and have them replace it, and rebuild the damaged head.  They should have a year warranty on all new parts and service.  If you had a local mechanic do this, you can ask what their stance is on covering their work.

What can happen in most cases with inexperienced mechanics is that when they install a new balance belt, they over tighten it.  After time, that belt will snap.  Normally, that's not a big deal.  But if your engine is at high enough RPMs, the broken balance belt can slam into the main timing belt and take that out too.  Most 4-cylinder engines that Mitsubishi produces is an interference engine.  This means the pistons and valves can occupy the same space.  What prevents them from smashing into each other is the timing belt.

The worst case scenario is that you would need the head rebuilt or replaced with a used head, and possibly replaced the pistons if they were damaged. You'd obviously need a new timing belt.  A head rebuild could be around $600 plus the cost of replacing various other components.  But talk to the mechanic shop that performed the timing belt change.  You may have success with them admitting they did something wrong and they may get you up and running for free or at least give you a better deal.
Good luck!