Hello @Liliia Sabitova, 

You will see the phone number for your landline contract: 

• in the customer center on the home page
• in the MeinMagenta app on the home page
• on your landline bill
• in your contract documents
• in the router settings (accessible via the direct address of the router, e.g. speedport.ip or fritz.box)

If you have any more questions, feel free to let me know. 😊

Kind regards

Belana