Tell whoever you speak to, that your sim card needs to be re-registered for the mymtn / internet APN.2 calls this morning approximately 2 hours each call. And still nobody can explain why my sim card ain't connecting to the net. Been over a week now.
In my case, if I used the Afrihost APN, internet worked. As soon as I used the mymtn or internet, there was no connection. My guess is your line has lost access to the mtn vanilla APN's.
