Dealer stripped threads in Hub ?

Hi, hoping someone can help me here, my wife bought a brand new Fiat Ducato 180 10PAL Schlafkabine-Webasto back in 2008, it has only ever been serviced at the our local dealer we bought the car from, took it in for a service and two new front tires last Thursday and got a call saying the front nearside hub has stripped a thread for the wheel bolt and it is a £305 repair to replace the nut! They said it was from corrosion and then told me the bolts appear to have stretched? Also stated that all the wheel bolts show this problem and that all the hubs will need a repair as the threads might strip and we can potentially have a wheel fall off whilst driving.

I have never ever heard of this problem with any car ever! I think that the wheel bolts have been over-torqued by the dealer. No one has ever had the wheels off except this very same dealer. I think they stripped the wheel bolt and hub thread and are trying to get me to pay for their mistake.
I found a hub studs on http://famaga.chfamaga and thinking of bringing my car back and trying to replace them by myself?

Is there anyone on here who has ever heard of this problem with the Fiat Ducato 180 10PAL Schlafkabine-Webasto? Our van has 41000 miles on it and has never had a problem before. Our car is in immaculate condition, no rust or corrosion, has not been abused and has had full service history from new with the very same dealer we bought it from. This is the third set of front tires fitted to the van, so it has not had the wheels removed an excessive amount of times.