Refund in progress for 6 months... and waiting

In April 2021 I changed my data contract to prepaid because it had expired. To my surprised I was then billed in May for the same contract. Upon querying it and it was concluded that I'm due for a credit on that bill. 3 months later I am nowhere near getting that credit even though it had been sent for approval. The story I get is that it should have been done and they don't understand why it is not processed. I've had 5 agents escalating the issue and it all just ended there. They keep telling me that I must wait. I came here and complained and they responded saying it has been sorted while it is not true.

I am extremely disappointed at the level of service I am getting. I am at the point of giving up on Vodacom as my service provider if this is not resolved.