Exceptionally poor customer service at Vodacom

I did a sim contract renewal through the retentions dept at Vodacom. The gentleman who upgraded me said they wanted to retain my business since I had been with Vodacom for 25 years. He then offered me a R1000 voucher to use at any retailer but said it would be sent electronically to me on the 1st of Sept. That did not happen. I called in on the 1st and they said there was a delay and I would get it on the 16th of Sept. I called again and they said there is no record of this on their system. I told them to go and listen to the recordings of our conversation. The retentions dept who offered this to me then started sending me to customer service dept, who in turn sent me back to retentions. No one knows what they are doing there. No supervisor is willing to help even though I have asked for their help. I think it is time to exit from Vodacom as they are not interested in my business.