Employee purchased airtime on account ***

I have a Jet account which I paid off a whilst and had requested for it to closed but never waa. The next thing I have debt collectors calling me telling me that I have a overdue amount of R241. 46 only to find out someone had bought airtime vouchers. I submitted an affidavit to them and was told the ***** unit would investigate the matter. Whilst waiting to hear feedback on who is responsible for this I get calls from lawyers threatening legal action. I am extremely disappointed and appalled by their inability to investigate and suspect this could be the trend of workers buying airtime on customers account without the customers being aware. This is a violation of consumer Rights as many may be forced to pay for services never rendered. I have spent hours on the phone calling but even employees who answer phones are not very helpful. Patience