Audi a4 cabrio 2.00tdi 2007, oil pump failure

HI, My car has been recently been diagnosed with a total engine failure following the oil pump failing, this was caused by the oil pump shaft wearing at the end, i have an independant warrenty on the vehicle but they are refusing to pay as they say its wear & tear so im going after Audi, they are willing to cover 25% of the 8k repair costs! which i think they should cover 100% of the cost as i feel the offending part was a manufacture default and not fit for purpose. The car has only done 55k is it a known and common problem with these engines and has anyone had the same problem and successfully got Audi to cough up, i have been told that Audi changed the design of the shaft/pump but would not disclose the reason why, should of they had a recall on these engines but just buried there heads!!
Look forward to some interesting replies

If you have not posted this in the A4 forum, I guess you should do so, I think this forum is aimed at the original 80 based cab.
Having said that, my 2p worth.
The warranty, I think they are trying it on and it has succeded, have you read the small print, is wear and tear valid? Do you agree this is fair wear and tear which was forseeable and avoidable?
I also agree the part has failed, due to defective design/manufacture, how long ago did you buy the car, whoever supplied it could be liable under the sale of goods act, goods need to be of satisfactory quality and fit for purpose, contact trading standards for some assistance.
VAG apparently now cover the cost of pd injector failures on those 16v tdi's, maybe they have something on the oil pump issue? Try Audi UK and browse some US forums, they are better at litigation and Audi cave in more easily in the US