Upvote:2
Spirit's rules are spelled out here: https://content.spirit.com/Shared/en-us/Documents/Contract_of_Carriage.pdf
My read is
What options are ahead of me, both for demanding ... compensation
There is no compensation beyond the refund of the original fare.
I bought their trip refund policy add-on
That was probably a mistake. These type of insurance rarely cover anything that the airline doesn't have to pay anyway (without insurance) and there tend to be LOTs of exclusions. If you are worried about not being able to take the trip, you are better of with 3rd party travel insurance.
Sorry, you got what you paid for. Section 8.1 is a particularly fun read
8.1 Spirit Airlines Responsibility for Schedules and Operations Times shown in a timetable or elsewhere are not guaranteed and form no part of the terms of transportation. Spirit may, without notice, substitute alternate carriers or aircraft, and may alter or omit stopping places shown on the reservation. Schedules are subject to change without notice. Spirit is not responsible or liable for making connections (on its own flights or flights of any other carrier), or for failing to operate any flight according to schedule, or for changing the schedule of any flight.