Employee makes mistake on payment

At the month end of July I went in to a vodacom store to pay my fibre contract as I do normally each month except this time a week later when I got my statement it was completely wrong. What happened was that the person doing the payment had made an error when entering my account details after she confirmed it was my account. After this I was contacted by vodacom for not paying my account where I informed them that there has been a mistake and they told me it could not be rectified without proof and my statements were not proof enough. After more than a month of struggling and them deducting more than double the installment my payment was found after I had gone to the store multiple times and the assistant manager helped me find the slip for the payment I made. At this point my credit score was negatively affected because of an employees mistake and the only thing that was done is for them to refund my account of the normal payment. They cannot fix my credit score and the debit order bounce amount was not compensated back to me either. The person who did the payment was not reprimanded in any way to make sure this doesn't happen again. I feel that vodacom owes me more because of the amount of time it took, the financial difficulty they put me through this time as well as the stress that comes with that, my credit that was impacted and the hours I physically put in to fix this. This is the hartbee****rt village mall branch. Once again thank you to the person that actually assisted me but vodacom you can do better