Handset Charge

in November 2015 I phoned vodacom to inform them that i will not upgrade my contract and thus they must stop billing me for the handset end of January 2016<br> <br> they did not billed me for the handset February 2016, come March 2016 received my inv with correct subscription bill but the debit order went of with the handset charge as well ( handset charge not on inv), i phoned them and were informed that they migrated to a new billing system and will look into the problem. I phoned them a week later, still no progress. received my April Inv today, guess what, got charged for the phone again. Can someone from vodacom please respond to me to rectify the billing issue<br>