Certainly it is possible to deactivate the Mobile-Tan system. To enable us to deactivate the system for you, we need valid proof of Identity. Please send us a two-sided copy of your ID via fax to 030 / 66 400 138 or via e-mail to firstname.lastname@example.org.
If you can only provide a passport or the address of your ID is different from the address you have entered into our system, we will require proof that you are living or have previously lived there. A copy of an official writing to the address will be sufficient to proof your identity.
Subsequently we will deactivate the Mobile-Tan system. Afterwards you could login and activate Mobile-Tan via Google Authenticator for a new device.