My line is not working

My MTN line have not really been working for some day now, the bars signifying network is always there on my phone but I can't check balance or do anything ussd. I can't call...

I hope my question will be answered.

Please I can't make calls and others are saying my number is not reachable please I really need help

Network service just went off my line since Friday 15/03/2024, and I can't receive a message or call even OTP I can't receive it. My line is 08040421108 and I have linked my NIN...