News back from independent engineer says that the Turbo failure was probably caused by the Turbo 'ingesting' something and NOT lack of oil. Does anyone know how this can happen ?

the car just lost power, I turned off then on again, it then died and wouldn't turn over, the garage that installed the turbo don't reall want to know and I'm now left with a car worth £4k with a repair bill of nearly that amount !!

Prior to the breakdown I was getting around 53mpg (which seemed unusually high) I thought it was great - is this a sign that there may have been problems with the turbo ??

Turbo blew on my 320d and I paid for a replacement to be fitted by a local garage around 3 months ago. Last weekend the engine siezed after a loss of power and a puff of smoke out the back. The garage are telling me the turbo's gone again, but this time blown oil through the engine which is gonna be VERY expensive (probably more than the value of the car) to sort. They're telling me that the turbo was starved of oil but I only checked it last weekend and the oil level was fine !! I'm expecting them to sort this for me as I paid for the turbo on the car 3 months ago. How can either me or the garage prove what's happened ??