Tensioner Pulley

Hi, I bought a 2002 Jetta 1.8 Turbo for my daughter from a local dealer in Clarksville TN. It had 105K miles on it when I purchased it. I bought an extended warranty, just in case. Well the “just in case” happened. While on a trip out of state the car broke down. I had it towed to the local VW dealer who stated the timing belt had broke. I contacted the warranty company to request it be repaired. To make a very long story short the warranty company said it’s not covered because the tensioner pulley broke first which in turn caused the timing belt to break. Of course there is a lot more damage than just the timing belt and was told it would cost about $5K to be repaired. The repair would be covered if the timing belt alone caused the damage to the engine but the warranty personnel say the tensioner pulley is what caused the damage and therefore they will not pay to fix my daughters car. I would just like an unbiased opinion.

1. Would you consider the tensioner pulley an internal engine part?
2. Is there a way to definitively say which broke first the timing belt or the tensioner pulley?

Holly