Sidenote, I have a feeling that’s straight up illegal under contract law. IANAL though.
Edit: Just so ppl have something specific: you bought access to the service. It’s probably gonna be limited in the User Agreement as “if this service has to be shut down, you agree to lose your access and you don’t sue to get your money back”. But this is a backend migration and I’m fairly sure this is not something they had in their original contracts. That’s why sniff a broken contract and when they don’t refund your money, I sniff broken laws.