Don't! Just don't book with airtickets24.com! My flight got cancelled one week before departure (just before christmas= no available flights) and where supposed to get 50% back from my 320€ ticket but only got 69€. Their telephone service where quick but with the time difference it was difficult to find the time. I would rather pay more for another company that promise you full refund and have a lot of different airlines that can offer another flight if yours get cancelled.