No help - Vodacom is *****ing money from bank account

I upgraded in November 2017 and was told I had 14 days in which to change my mind about keeping the handset or cancelling the upgrade. After about 3 days, I contacted Vodacom to cancel the upgrade, and returned the handset to them, sealed and unopened. the lady who assisted my in cancelling the upgrade and dispatching the courier to collect the handset didn't in fact cancel the upgrade (this was early December). I then was double debited in Jan 2018 for the handset and airtime contract, which i believed they would just reverse later or offset it again on my February premium. I contacted the call center in Jan 2018, and was then advised that the upgrade had in fact not been cancelled, even though they acknowledged i wasn't in possession of the handset any longer . fast forward to Feb 2018 - they are still debiting my account and no refund. reference: 1- ********** **********