Mtn is a ****

Mtn South Africa has become a sore in my life. I use prepaid phone and for the past 3 months my airtime has been vanishing from my phone and I checked for active subscriptions but I don't have any.if it's not that I get loaded with 15 gig of data and I'm told I need to pay it back even though I didn't authorize or request to be loaded..I'm sick of this bull****