[9eor9]

I found a register form of my CallYa which came with a Quelleshop-VF125.
Normally this way should work with all CallYa but I cannot ensure.

Write a letter with:

Your CallYa telephone number
Name
Surname
Date of birth
Street
Housenumber
Postcode
City
Country

Number, place and date of issue of your Passport/ID card
For non-german citizens: Number of your residence permit

Wanted customer ID (4 digits, used for the protection of yor personal data. This is asked to prove your identity when you call the hotline), you may choose any number.

This you either fax to 0049-2102-98 60 20
or send by post to

Vodafone D2 GmbH
Vodafone D2 CallYa Team
Postfach 101502
D-40835 Ratingen

I would recommend to add a copy of your passport too.
Whether they accept addresses outside Germany I don't know.

Good luck