Overcharging

I upgraded from a blackberry to a Samsung in March 2014. Freddie Hitch**** assisted me. Had a huge issue with vodashop the Grove as my phone was not working properly and I received no help from them. Eventually Elroy assisted me and I received a new phone. On Sunday I realized Vodacom has been charging me BIS for the past ten months for the blackberry that hasn't been in use since the upgrade. Nonkose at Vodacom customer care told me it's Vodacom the Grove's responsibility to refund me, Phillip at Vodacom the Grove said they will only refund me for 3 months. WHY???? It was Freddie's responsibility to stop the BIS, why don't you train your people correctly? Why must I foot the bill for your incompetence. We've been with Vodacom for so many years, and never had such bad service as this year with Vodashop the Grove, and I see I am definitely not the only one!