Hi @maribel999
The information you received is incorrect. All telecoms companies must accept the document ‘Aufenthaltsgestattung’.
The law regulating this is the telecommunications law. Paragraph 172, section 2 covers what type of documents the companies have to accept as a form of identification. Under number 5, you can see ‘Aufenthaltsgestattung’ is written:
https://***.gesetze-im-internet.de/tkg_2021/__172.html
I recommend you return to Vodafone with this information. If they persist in refusing to register you, you can contact the organisation called ‘Verbraucherzentrale’.
They are the organisation that protects consumers in Germany and so can help you if you have any issue with a particular company, for example regarding a contact you enter into with them:
https://***-verbraucherzentrale-de.translate.goog/beratung?_x_tr_sl=de&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=wapp
Best,
Éanna