With cancellations, your rights derive solely from the airlines' contracts of carriage, plus relevant principles of general contract law. And because no federal regulations apply, those rights are not uniform but instead vary from airline to airline
Most airlines will refund a ticket that was cancelled without a reasonable replacements. You're not going to get a refund if they put you on the next flight in 45 minutes, but probably will if there's nothing for days.
But the reason you save (in theory. Maybe) with Spirit is that they are cheap, inflexible, and make their money nickel and diming you every chance they get.
You may get a refund from Spirit, but if I had the rank the likelihood by airline, Spirit would be at the bottom.