Being billed different amount than on contract; reported dispute and no response.

I have signed up for a Telkom uncapped Internet Fibre 10Mbps for 24 months for the cost of R800. However, when I look at my monthly bill I saw R953.86 since I signed up and this month it was R814. I have only used the broadband service and have previously raised this with the service desk as a dispute, and have directly communicated to a helpdesk staff via email with detail. This was a month ago. I have not yet received a feedback on the dispute but I have still received another incorrect bill, and have also not been refunded for my previous overpayments for the service.