Data disappearing / being depleted

Since yesterday my data gets depleted without any reason or me using my device. I sent a DM tweet to MTN last night and this morning but still waiting for a response. I then called them but the gentleman who answered the phone couldn’t help me. He told me that he works for an outsourced company who doesn’t have direct access to MTN systems and therefore cannot be able to advise me what’s happening with my data. So I need to know who the is able to tell me this.