I'm not sure it's even possible to have a valid contract with an unknown party...
I'm not sure it's even possible to have a valid contract with an unknown party...
The provided information on this website is not enough to do legally binding business (at least in some parts of Europe, it's not only Germany).
As far as I understand German law is very flexible about what constitutes a valid legally binding contract.
§312f for example defines that customers must receive "a copy of a contractual document signed by the contracting parties in such a way that their identity is identifiable" (translated via DeepL).
A simple mail address is not an identity in German law, especially not when doing business with B2C as you always have a 14 day period to cancel your order (except for downloads and various, special products).
edit: If you want to cancel, you must be able to do so via (offline) mail, too.