Incorrect Billing and poor response from Telkom

In December 2018 i took a voice and data contract with Telkom. I was advised that i could stop the contract at any time. My monthly repayment was a set R605. However as the months progressed my bill began fluctuating. Some months the bill amounted to over R800 with the minimum being around R600. I have made numerous calls to Telkom and have received no joy. I then took out another contract with Afrihost and tried to cancel my Telkom contract but i was advised that i am bound to a two year contract ending December 2020. I asked for the contract voice recording which i was promised i would receive and to date, the consultant has not called me back. I have written emails to the said consultant advising him that my monthly bill has escalated and that the matter needs to be resolved but i have still not received a reply. I have been sorely inconvenienced and the lack of feedback from Telkom is frustrating. Telkom's service is very poor and it is sad to see how they handle customers who have been account holders for more than 20 years.