Please how do I get my keep my line going

My wife MTN line has been ban and she couldn't link the nin with the code *996# even when her line had been linked before

I need to retrieve that line to re-register my WhatsApp account, as the code keeps going to that line during the registration process. Kindly assist please. Many thanks

Pls help me unbarred my line back

Calls cannot be made but I can receive calls