CHARGED INCORRECTLY ON BILL AND NO ONE ABLE TO DO REFUND

I recently upgraded my contract and the sales agent that assisted me informed me that there would be no additional fees (early upgrading/migration etc) I asked multiple times if this was the case and agent even confirmed how much I would be paying.

Received my bill and was charged R800 more than I was told by the agent, when queried with MTN they confirmed based on the call recording that I was indeed not supposed to be charged based on what the agent had said.

Since then (1st Dec) I have yet to receive a refund for this extra charge and have spoke to multiple agents all who have said they will assist me and yet every time I call there is no records of my previous calls to agents and no actual queries open.

Last resort seeing if they will actually respond or assist but I doubt it.