MWEB fibre service is shocking

I subscribed to MWeb fibre about 2 weeks back for a 40 line but only average between 5 and 18.I have repeatedly tried contacting them with limited success.I hold on for 20 minutes or more and when I finally get to speak to someone they cut me off. I am NOT prepared to pay for 40 when I get nowhere near that. I was in between told to buy an ethernet cable at my cost to test THEIR product.This I have done but simply cannot get hold of them. I am at my wits end with this bunch.I will NEVER recommend them to anyone.