Telkom cancellation ... no response

I took out a LTE contract with Telkom, however, have been struggling with connectivity. Technicians came out and confirmed that the towers were overloaded and they could not do anything to improve my connectivity. They also confirmed that I could cancel without penalty.

Since then I have been trying to get my contract cancelled, with no luck. There is no way to directly contact the cancellations department - my issue just gets escalated every time I phone, with no feedback. I have been paying my subscription for months now, however, I almost never have sufficient internet to even browse a normal website.

Not sure how to get Telkom to cancel my contract ...