Ci, if your trip was just 'flight only' then I would suggest you contact IATA as well as ABTA. If an airline 'defaults' on the contract to fly you on the booked date then you are entitled, by law I believe, to compensation. this would normally be putting you up in an hotel, food, normal expenses etc. It wasn't your fault you couldn't fly (and it wasn't theirs to be fair) but the airlines are claiming compensation which should, in theory, be passed on to the passengers. I would certainly write them a letter/email asking for compensation (the cost of staying longer) and ask for a response within so many days or you contact a lawyer. If your flight is only delayed for so many hours ( from what I remember, 5) you are entitled to free refreshments. Good luck.
ps I never fly Thomas Cook unless it's an emergency, they're crap