I can't call or dial any code on my MTN , but the data network is working . What is the cause ?

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...

It might not work because of the network

I subscribed for my smart data 10,000 for 53gig this morning and I can't use it why what happen mtn give solution to it...