Issues with Telkom

Telkom sales had called me with a better plan to add to my wifi system they then added this plan to the incorrect wifi plan. I called them to cancel it and they did. However they did not cancel the upgrade period that was added on so now my wifi contract which should be ending in this month is now ending in 2 years time . Furthermore they offset the credit limit to R500 which was previously R50, and upon enquiry (only knowing this after I received a bill)their back office (Tanya Mathebe) advised that there is nothing that can be done. So I had been debited for R500 because Telkom didn't complete their process and since the data was used the payment needs to be made even though I was not aware that I had an increased limit and I am aware that if I pass my R50 limit the wifi will cut off. I am currently been trying to get telkom 180 to sort out the upgrade period and they have passed me on to 10213, which state they cannot help me because the department's I get put through to do not deal with my issue and they are not prepared to let me speak to someone regarding the R500 I have been billed because according to them that matter has been dealt with. Please can I get some assistance.