Our 2007 Audi A4 Quattro went in for an oil leak at the top rear of the engine and a turbo underboost code that came on. They found oil leaking from an o ring on the face plate of vacuum pump and replaced vacuum pump. They then found a trouble code that said the turbo recirculation valve had a torn boot and replaced the recirculation valve. Drove car home from shop, less then 60 miles, and the check engine light came on on a Friday. Drove the car maybe 10 more miles over the weekend. On Monday about two blocks from home the car just stopped running. Had it towed to the same Audi Dealership. They called and said they have bad news. Told me that the high pressure fuel pump seized which made the cam follower seize which seized the rear timing chain which made the chain break cause bent valves which caused a hole in the valve cover and it needs a new head. The service guy then said it's not a fault of theirs and had nothing to do with the repairs that they made. He said he spoke to another tech to confirm this. He said it will be $4,600 plus tax to fix the car. This is on top of the $1,500 that I just paid them for the other repairs. Can someone tell me if their initial repairs could have caused the catastrophic damage.