at such low miles? are these made of straws. the evos overstressed turbos do not blow like that so early.
I have to agree. IF the turbo has blown a seal then it explains everything, the only reason to change the intercooler would be if there was a serious amount of debris in the cooler that just could not be flushed.
This sounds even more like it was run without oil and the turbo would likely be the first thing to fail. It could be coincidental but it sounds unlikely!
However - whilst you are not picking up the bill for this one and have no way proving that any other damage has occured you may as well just accept their story and let them sort it out