Vodacom agents who give out false information to customers

I was due for a data sim upgrade of which I called the call center. The agent advised me I can keep the Sim card for the same fee I was paying. Next thing, 2 days before my debit date I receive an invoice that is 5 times the amount I initially knew to pay. Called vodacom, I was sent from pillar to post, agents dropped my calls, and I was on the line the entire afternoon. Told them I'll pay the fee I was aware off and I need an investigation to be conducted. Nobody wanted to take accountability, and I requested the call recording but till today nothing has been done and I haven't received that recording. I've been flagged as someone who didn't pay vodacom but I did pay, and they were made aware of the whole thing before the debit day.