Refund/Correction not done as promised & Bad Service

I run a transport business and I have multiple vehicles on tracker of which I am billed on a monthly basis. In October 2021 billing I was billed for additional services for SMS alerts messages of which I was not aware of and did not activate on my side. This was an additional R1600 on my normal bill for the month. I did advise them that I did not receive any messages on my side and I did not activate this service mid October before my debit order goes off.

I did notify the billing dept and they advised that a investigation will need to take place of they did and found out that there was a system error on their side and advise me that they will sort out before my debit order goes off. This was not done as promised and the full amount was debited from my account. I then call and send email to them advising them and a few days later they respond to say they have loaded a refund and should take 3 days to reflect into my account, this was towards the end of Oct 2021.

I wait for more than a week with no refund, I then call a again and go thru the same process only to be told that a refund was identified but not loaded hence I need to wait another 3 days for it to be loaded.

Today is the 15th November 2021, almost a month after advising them of this issue and I have still not be refunded and nor have they responded to my emails. When I called and asked to speak to a more senior person than the agent, they say the supervisor will call me back and I am still waiting for that to happen from last week.

Can someone senior please call me ASAP as this matter is still pending.