How do I change my number if my previous number is lost or terminated?

Option 1: Open the stc pay app, go to Account settings, select change phone number, follow the onscreen instructions Option 2: Open the stc pay app, login as a new user, choose change phone number and follow the on-screen instructions.
Is there a maximum age limit to register?

Yes, customers aged 75 years and above will not be able to register.