I was in a similar situation due to the hurricane. (Not on the night canceled by the hurricance, but the next night, when the airport was still closed.) They gave me credit that needs to be used "in the next year or two" but were completely unable to get me tickets to another party or process a refund.
If Disney doesn't issue you a refund, the tickets will stay on your account and you can apply them to a future MNSSHP or MVMCP event. For example, we had to cancel our MNSSHP for 2021. Ticket services then helped us roll those in to MNSSHP 2022, once those tickets were available. Then we decided we'd like to go to MVMCP instead, so once again we made a call to ticket services. You're probably already aware, but make sure you have your original method of payment available. The tickets we have were $10 or so cheaper from our original purchase so they put the money back on the gift card we originally used.