Why I mine not receiving code on my sim

I want to change a name on a customer sim and the sim is not working please so I can't receive code answer

Why can’t I receive code

Been trying to login my iCloud and they have been sending code to my mtn line but I have not received...

I am unable to receive whatsapp code for my whatsapp registration on my number 08063409253, i have tried several times and its not working, i contacted whatsapp and they told me...