No feedback from accounts/complaints department

I upgraded 2 of my accounts in March 2017. From the first month of the upgrade there is a double handset installment on one of the accounts. I queried it at the Vodashop in East Rand Mall where i did the upgrade. they could not resolve the matter. I then emailed the ********** address multiple times with all the details and no feedback from them at all. I phoned Vodacom multiple times and no body can assist me with this matter. i have now paid 6x R389 too much because it is indicated on the invoice that there 2 times handset installment. I only have 1 device for this account. I need assistance because Vodacom does not care to keep there customers happy. They just care about revenue.