My data bundle disappears everytime I recharge.

I have a problem that every time I recharge and convert my airtime to a data bundle, after a minute or so it just disappears. I noticed this a couple of days ago, it then happened today (03/03/2016) when I call MTN to enquire about the cause of this, they cannot tell me why this is happening instead they tell me it \could\" be possible subscriptions which I do not have any knowledge of. This is ridiculous!<br> <br> I want to know why my data bundles disappear, the explanations I got from the two consultants I spoke to (Wendy & Paulina) are not satisfactory. I do not have any apps that are running on my phone's background, I logged everything out. Someone please help before I lose my mind, I've had it with MTN's bad service. This is really unacceptable. I need this resolved immediately and I want all the data I lost mysteriously refunded."