I don't think it is a payment issue. At least in Brazil (where I live), a registration (which can be done directly with the .br registrar, not necessarily third parties) costs less than 10 USD a year.
vlemmy.net was registered less than 2 months ago, for 5 years. I suppose (hope) it was already paid for 5 years.
it's strange that it's parked at a dynamic dns service though
dynu.com is a dynamic dns service. I don't think the maintainer of vlemmy.net would be running the instance from a dhcp (variable) IP, to justify using dynamic dns.
Or is it usual for people to run instances from their homes using common ISP subscriber variable IP addresses?
Even more strange that it was registered just last month, according to whois. Is vlemmy.net that new?