I have been having the same issue with my SIM card (i opted in from an MTN prepaid sim, round about the same date as "Tytn Rulez"
Subsequently I have been given a workaround by Domenico on the 5th of February 2017, to add a fullstop to the APN server, i.e afrihost., however with shock realised that I am connecting to the internet via the MTN default APN on the 16th of February, as I have been getting warnings of out of bundle usage.
I logged a ticket on the 16th of February (KCB-110-58822), following up almost weekly from that day, as that workaround is not financially viable, as well as requesting a refund for uneccesary cost incurred on my account.
I have now replied on the last mail I have received from Valentino on the 26th of February, as it is getting to the point that i am loosing my confidence in Afrihost and MTN to resolve the issue.
I would have originally restrained myself from doing this post to MyBroadband, but I think it is now neccesary to state the reality of myself still experiencing issues with the service(16 days after it has been concluded that the issue is with the SIM card not provisioned on the MTN network, to access the Afrihost APN), and I am hesitating to endorse Afrihost as your one-stop service provider for Mobile/ADSL and Fibre.