Sales Agent error in codes costs me thousands

In February 2014 I signed for a month-to-month sim only contract from Telkom mobile in Rustenburg (Waterfall mall) with specific request for month-to-month since I only need the sim for 1 year. In February 2015 when I wanted to cancel my contract I was told I have to pay a R800.000 penalty fee for breach of contract and thereafter will still be billed R299.00 per month without service delivery, according to them I have 24month contract. After reporting the incident, being to a Telkom store and contacting the call centre no one reports back on their findings. I had to email them the contract and the brochure with the promotion they ran that month, which I did. After weeks of waiting I could not get a hold of the sales agent, Susan Nel, because they refuse to answer their office lines. After emails are sent the agent phoned me stating that she was under the impression that the problem was solved. Apparently the superior to whom my documents were sent, ignored the request because she could not see the details stated in the brochure for the promotion - no one contacted me to say that anything was unclear. Thereafter I realised that I no longer receive service, yet are still billed!