Run Flat Tyres on 5 series GT 2010 model

Just had my 530 GT serviced at 17K. Exactly the same problem with threads showing on the inner edge of both rears. BMW are not interested, claiming i must have knocked the tracking out by hitting a pothole. I called BMWUK customer service who listened attentively, called the dealership and then called me back and repeated verbatim what the dealership had told me previously.
Waste of time BMW. I swore before i wouldn't by another BMW with run flats and i made the same mistake.

Same problem in California. Dealer said factory did not align properly Cost me $1,800 If this is factory problem and not users failure we should get our Money back from BMW don't you think?