Don’t want to get into too specific a detail as this is a live dispute but i'm looking for an overview strategy here!

The bones of the issue is that the organisation purchased tickets for 2 foreign nationals visiting us; we got one of the names misspelled and that individual was required to buy a 3rd ticket at his airport. The other gent got prevented from leaving at his departure airport due to travelling on a valid personal passport, however his authorities maintained he had to travel on a government passport (which had not been issued to him) so he didn't travel (but still wants to).

Guess what.. klm maintain the 2 tickets we bought are non refundable and that’s the end of it. £2,000 at stake here!
Thoughts on a strategy?