Vodacom billing my bank account *******ly.

I had a Vodacom cellular phone whilst I was working for the City of Johannesburg. I left the City of Johannesburg on the 6th November 2014. I left the cellular phone and SIM card behind as they belonged to the City of Johannesburg. My cellular number was *** and my account number was K***-8. The problem is that Vodacom keeps on billing my account whereas the cellular phone and SIM card are now used by another City of Johannesburg employee. Christine Mogopodi who is an administrator at the City of Johannesburg informed Vodacom in February 2015 that I am no longer employed there. But they keep on billing me.<br>