Originally Posted by visualAd

BA need to honour their original price or compensate you. As with all these things it depends to what extent you want to persue them. I would suspect they would give up before it got to court though.

I would make a complaint and ask for it to be escalated immediately. Book the new ticket as soon as you are able and bill BA for the difference. Make it clear they you are not asking if they would be kind enough to pay it, you are telling them to pay it.

Be prepared to lose but I like I say, don't think they will take too much pressure to back down. If you have a receipt and e-ticket I doubt they much of an argument in their favour. The one of "you should have known" is very unsubstantiated and subjective. €2000 is pocket money to some people, to others it is 12 months of dedicated saving.