So I know this is a bit of an old thread...but I'm having a similar issue now. This is what happened...
I was having some connectivity issues on my home Telkom LTE...so I checked clientzone to see how much data I had on my Afrihost 8GB package that I use on my phone. It said I had 3.15GB remaining.
So I fired up my WiFi hotspot and connected my laptop. I immediately began having connection issues and after reconnecting a few times I got the "out-of-data" screen when connecting.
I checked clientzone again and I still had 3GB of data remaining so I sent a support ticket. In desperation to get some work done, I changed back to the MTN APN where I still had 2GB of data (which was depleted after 101MB of use but that's another story)...however, my laptop was still displaying the Afrihost "out of data" screen when connecting, even though the MTN APN was selected. I restarted the phone and laptop as well as "forgetting" the WiFi connection and reconnecting from scratch...still the same Afrihost "out-of-data" screen...
So eventually I deleted the afrihost APN from my device (I can always re-add it later), restarted phone and laptop, forgot and reconnected to WiFi and it was working....
then I get an sms saying I've used 83% of my Afrihost data cap and I have just over 1GB remaining....and shortly after that...another message saying I've been capped...this is quite impossible due to the fact that the APN wasn't even on my phone at that stage...
I wonder if this disappearing data is connected to MTN's disappearing data?? But still I need someone to help me out with this because this is my work phone and I need that data back.