Did you have an E-ticket number?
Is the flight actually canceled as in the plane isn't flying or is just your ticket that is canceled?
What was the reason for cancellation?
If you were properly booked and held a confirmed ticket and this is a case of IROPS, then it is up to the airline to fix it and they should have relevant regulations.
If this was some messup by the OTA that never issued the ticket or some other such problem then it is up to them to help you out.