Chrysler Repair: timing belt change, timing belt tensioner, chrysler voyager

Question
Let me give a little history first. I was driving from New York to North Carolina with 2 children and 8 months pregnant. I drive a 2000 chrysler voyager 2.4L 4 cylinder. I stopped for gas in Maryland and discovered radiator fluid leaking from the car. So I took it to a dealership who said it was the water pump and suggested replacing the timing belt at the same time. I agreed paid for the work and continued on my way. I had traveled just over a hundred miles (right outside of Richmond, Va) and my car shut down on the interstate. I had it towed to the nearest dealership. They informed me the next day that it was a bolt in the timing belt tensioner that had snapped causing the breakdown. They also said that it had nothing to do with the previous work done on the vehicle and therefore would not be covered under the warranty.  I was wondering how likely it is for that bolt to just break. It is an automatic adjusting timing belt tensioner. I was wondering if the bolt could have been fractured by over-torking or any other mishap when replacing the timing belt.  

Answer
hello monica
this is the dealer they over tourked it and they know it you fight them you should not have to pay a dime for thire mistake . if you need more help you let me know i will help you any way i can . good luck with the new babby . and you have a pretty name pete