Not getting what I am paying for

I have been a MWEB customer for many, many years and the service has always been excellent. That all changed when our fibre line was installed. Paying for a 10mbps and since it was installed it has never achieved this speed in the evenings. During the day it is generally Ok but come 17h00 /19h00 the speed drops to around 3mbps. There is an ongoing technical query open and the "experts" say it is either data interference or cloud services running which I don't believe. As a test I linked all our devices to my neighbor's fibre (it is about 10metres away) which is supp**** by Telkom and got a perfect speed when ours was only 3mbps. In an endeavor to get a better speed in the evenings I phoned MWEB on 7 November 2017 and app**** to upgrade the line speed to 20mbps. Acknowledgement SMS received followed up by another one on 9 November 2017. Contacted MWEB on 9 November and after much investigation and holding on they said they had made a mistake and would sort it out. I asked to speak to a manager and was told she was not available and the MWEB call centre person could not guarantee that she would phone me back. He was right I have not received a phone call. Today 13 November OpenServe arrived at my home to install the fibre line. This gentleman left but came back 10 minutes later to test our line. He plugged his laptop into the ONT and tested the Telkom line which gave a reading of 20mbps. Then he tested the MWEB speed by connecting to the router and got 6.89. I have photos to prove this. Enough is enough this is a MWEB problem/fault and I have been more than patient. Would I recommend MWEB, never again. The solution is for my fibre line to be cancelled so that I can take out a contract with Telkom and the amounts I have paid for the fibre line to be refunded I have paid for a service that is not being provided.