I am having data issues, and having issues with my Afrihost account as well (linked to my MTN contract).
I just swopped my network mode from *WCDMA/GSM to *GSM only and it seems to be working fine for now...
Update: - MTN Advised that this is a CORE Network failure impacting nationally. They believe the issue is resolved, however will take time to stabilize across their network!
MTN is POS! Was with them for 10 years. 90% of calls were dropped daily (not even exaggerating). Canceled contract and ported to Vodacom and haven't had any issues since.