Egypt Air cancells flights

We were a group of 22 people visiting Israel and flew by Egypt Air. While we were in Israel, Egypt Air cancelled our flight back and we had to stay in an hotel for an extra night. They flatly refused to cover our extra costs caused by their cancellation and the insurance refused to pay because it is the airline's esponsibility. International aviation rulles state that they MUST provide passengers with accommodation if they cancell a flight. They refused.