Being charged for data usage when not on their APN

I have noticed that almost my entire bill every month consists of data usages.<br> The strange thing is, I'm not using MTN's APN.<br> I'm using Afrihost's APN, and paying Afrihost for their data, while at the same time, MTN is charging me for the same data at out of bundle rates it seems.<br> <br> I have called call centre and enquired this.<br> They weren't very helpful and kept saying I'm billed for data, even when I told them I don't use their APN.<br> I've emailed customer care and asked them to provide me with logs to show when I connected to their APN and showing me the usage.<br> They escalated my request to data validation department, and once again, I never heard back.<br> I called in again last week and asked for an update and proof of my usage, and I am still awaiting feedback.<br> <br> I'm starting to believe that MTN is ******** money from many other people just like me, who might not know that they're paying twice the data to a company whose people have no idea how to set up a simple SQL query and provide me with the information I require.<br> <br> I work in the same industry and know that if I provided our customers with the same service that they do, I'd be fired.<br> <br> I am very angry and disappointed with MTN.