Here is how you can update your phone number or email address -
Update the app to the latest version from the App Store.
Login via Phone (if you don't have access to the phone, you can enter the registered phone number and receive the verification code on the email)
Once logged in, on the home page, tap on your picture and goto your information.
Tap on the field that you want to edit. It will ask you to verify your bank details for security purposes.
Once verified, you can edit the phone or email and confirm the changes.