Hey @KollerArg, welcome to the Community!
We hope you don't mind if we reply in English. If you'd like help in Spanish, you can reach out to us via email.
If you were supposed to be the admin of the Premium for Family plan, sign up for it here using your account and invite the members of your plan following these steps.
The user who accidentally signed up as the admin should reach out to us on Twitter within 14 days of the payment being made.
Hope that helps 🙂