I've been using the same x86 server for 3 or 4 years at this point, plus another arm64 one since they introduced them (so two years?). Never had them deleting anything, haven't paid a dime.

Paid tenancy is just a matter of providing a working debit/credit card. You don't need to actually spend anything to keep using the free tiers with resource protection.

No they only turn them off if they detect 0 load for a few months