Hi @Najiblara
Welcome to the community forums and getting in touch.
You can change your mobile contact number on your online account either via the app or through the website on the Account settings page. There will be a red 'EDIT' at the end of the current mobile number where you can change the number.
Please let us know if you are having any further issues or have any questions at all. We'll be here to help on the community forums if needed :).