Flight cancellations have become the norm lately and can be very frustrating. BUT you can get your money back on a canceled flight.
When you buy an airline ticket you enter into what is called contract of carriage which entitles you to a full refund if the airline cancels the flight for any reason.
This does apply to refundable and non-refundable tickets.
You are entitled to a refund if the airline issues a significant schedule change and/or you decide not to travel due to the significant delay.
One catch--the term significantly delayed is not defined so you may have a fight on your hands.
If you take your grievance up with the airline and don't get a satisfactory resolution you can take your complaint to the Department of Transportation.