MWEB's service stinks!

I have now paid 7 months for an MTN LTE contract which I took out from MWEB, but I do not get the service I pay for. The majority of the time last month I received download speeds in excess of 10Mbps and upload speeds in excess of 3Mbps, but sporadically the speeds would drop to below 1Mbps down and less than 2Mbps up or vanish totally. I keep records of these incidences and kept on reporting these to MWEB via my account on their website and Facebook Messenger and asked them to move me to another service provider to see if I can get better service, but they just ignore my plea and don't even bother to reply to my queries either anymore. When you try to get hold of them via their customer service number, you end up somewhere in the queue and then have to wait in excess of 10 minutes for someone to answer while using up your airtime. What must a person do to get satisfactory assistance? I rely on this service to run my business and earn an income!