POOR internet and NO joy!

Afrihost installed fiber at my home about 2 months ago, since the start I was not happy with the ping I had and for the first 2 weeks it was spiking badly and my 20mb fiber line was worse than my 4mb ADSL line. after a lot of talking and sending screen shots they finally got it down from 150ms to around 80ms. I decided that although it was bad I could live with it. A few weeks later however my download speed started to drop and ping spiked again to 150ms and download speed went down to 0.26 mbps. I finally decided that they are not giving the pure internet joy they said they will and that I will give them a month notice to cancel the account. But now they want to charge me R3421 to cancel a service that I only want to cancel because the service is poor! I always paid on time and just want to get over this but still they will not let me go without one last ***** you.