It happened to me, I arrived 48h late ! I started doing the claim myself but I honestly would not have the persistence to do it for months and do all the way to court.

But there is companies doing it for you, I found one online, have them my tickets and agreed that would take 30% of my compensation or 50% of a later had to be involved.

Few months later I received an email saying that I won 600€. They are keeping 50% so I will receive 300€. Honestly I should recommend anyone who had a delayed flight in Europe to try that.