If you can prove it their liability insurance could handle it. In my opinion unless the vendor is ethical you will need others that got the same fuel load at about the same time otherwise to prove your case in my opinion.

Some modern diesels can be really expensive to get by a problem like this. You will get the hassle at some point unless you fuel at basic high volume truck places in my opinion.

Newer volkswagon diesels are just one car that you should be really careful about this in my opinion. I have heard the costs can be very high and not covered even by the warranty. This just may be hearsay though