You can use your right of objection within the first 14 days to withdraw from your contract with IONOS.
If this two-week period has passed, you still have the option to end the contract because cloud servers aren’t bound to a minimum contract period. It doesn’t matter if you chose free Windows server hosting or the Linux option, when you delete the cloud server, you won’t be charged any additional costs. This also applies even if you have used up all your starting credit.
Cloud servers from IONOS are billed to the minute and you only ever pay for what you’ve used. This means that you don’t have to terminate the entire contract – just delete the server to ensure you're not charged any more. If you start using resources again, you will be billed for this use.