That can happen in the US too... When you agree to a contract you are bound to the terms of it.
Why do you think it is so common to hear horror stories about gym memberships?
But in your example no one agreed to the contract which means no agreement exists.
Generally you can say that payment was agreement to terms but that doesn't work if you deceived to get the payment.
> in your example no one agreed to the contract which means no agreement exists.
??? you agreed to it by registering a .at domain. There was probably some fine print at your registrar which says you agree with the registry policies