Pay back the money

We had my mother-in-law booked on a flight in May 2022 but she passed away at the end of March 2022. We had to wait for her death certificate and sent this as proof to Kulula so we could get a refund. This was done on April 1. It however seems that Kulula thinks this was an April fool's joke as no refund has been forthcoming. No response is given to emails, so what are we supposed to do? Just write off the money as they are struggling but the reason, they are struggling is bad service and no one trusts their planes. So Kulula if you don't want to continue alienating clients, pay back the money.