Billing mistake

Good day, Vodacom has been double charging me for one contract. They keep on phoning me to upgrade and I keep on telling them I already upgraded. I have 2 profiles with Vodacom, both profiles has 2 Voice contracts on. I only have one Voice contract. and one phone .This has supposedly been escalated 2 weeks ago, but no answer. I also receive no invoices, only one statement from the account I have with Vodacom for 20 years. Two debit orders going of my bank account and one is way to much. Can this be sorted please. I do not think it is fair that i have to follow up constantly as a customer.