Contract breach from Vodacom

I have been struggling with my internet speed for a month now,I am supposed to have a 40 mb/s line. I am not getting anything near that speed. Lucky if I am getting 5mb/s. I have submitted several service requests and Hellopeter complaints. Vodacom just closes the complaints.

Latest serve request no: SR190 ********** 69 I am getting no feedback, and today the Internet is not working at all. I will now proceed to lodge a non conformance at ICASA. I want to know how can I go ahead and cancel everything from Vodacom, since Vodacom is in breach of contract and does not deliver the service required as per the contract agreement. I will no longer tolerate the incompetence and lack of service from Vodacom. Advice me on the cancellation process, as this is a contract breach from Vodacom, I should not incur any penalties.