I can't receive call and I can't make a call with my MTN line

I can't make calls with my MTN line but I can receive calls and sms. What can I do to be making calls with it

I can't make calls with my MTN line but I can receive calls and...

I can't make call with my MTN line even when I want to check my airtime balance it can't even show me

Can't make calls on my MTN and also can't receive calls have try many things still not working and also MTN network not connecting why all most three weeks am in USA...