[PHXFlyer]

T&Cs

1.3. A Member may cancel his or her membership in the Club at any time by selecting the unsubscribe option within their FREE SPIRIT account profile or by notifying Spirit in writing at the address at the bottom of this page. Cancellations by mail will take approximately 4 to 6 weeks to become effective.

1.5. Dual memberships occur when members hold both Paid and Complimentary memberships. Paid memberships will continue and renew based on original membership terms, unless otherwise cancelled. No refunds, credits, or extensions will be granted for Dual memberships.

3.2. Upon Trial enrollment, each Member will be charged a fee of $9.00.
3.3. Enrollment fees are non-refundable, notwithstanding Member's cancellation of membership in the Club.
3.4. 60 days after Trial enrollment in the Club, and on each anniversary thereafter, Members will be automatically charged an annual fee of $39.95 for membership in the Club. Annual fees are non-refundable, notwithstanding Member’s cancellation of membership in the Club.
3.5. One (1) year after Annual enrollment in the Club, and on each anniversary thereafter, Members will be automatically charged an annual fee of $39.95 for membership in the Club. Annual fees are non-refundable, notwithstanding Member’s cancellation of membership in the Club.
3.6. Initial or renewal membership fees are subject to change by Spirit at any time without notice to the Member. Any increase in the annual membership fee will take effect upon renewal of a Member's membership.
3.7. A Member will not be entitled to any refund of any membership fees upon cancellation of membership in the Club.

When you ticked the box saying "I agree..." and clicked "Purchase..." you agreed to all of the above terms and more. Again it's very clear that they did not, under the terms and conditions, owe you a refund. They did give you a travel credit equivalent to the annual fee. I think that's fair given the circumstances.