MONEY BEEN DISAPEARING OF MY DATA AND AIRTIME

Please note that I have been very upset regarding my airtime and data that disappear. This is out and out theft apparently, the staff at MTN told me there is a company called "Uchater Silver" that take R15 a day. Who gave them permission to deduct this off my account because I am not subscribed to anything.

Please, I need answers as this been happening for a couple of months now!!!