Agreement not honored

I feel cheated by the Vodacom Fibre retentions team, as I was promised a R300 voucher by the consultant when she convinced me to not cancel my contract with Vodacom to move to another provider. Now when I call the support line on *** they are unable to identify who the person was that made these promises. In the mean time my package has been upgraded as I've electronically accepted the Terms and Conditions as I believed that Vodacom is a company that I can trust. Could someone please retrieve the call logs of the conversation that I had with the retentions department on 12 September between 12:10 and 12:50 from my work number *** to investigate. I expect that you honor your part of the agreement or else I will cancel my service as it is clearly a breach of trust if I was misled.