unstable internet connection

I am in contract with Telkom paying R1800 plus every month for a premium internet connection. For as long as we have had the line its been unstable, calling several times to Telkom for help. I am tired of calling *** and being on the line for 23 minutes without anyone answering and at my expense having to pay for this call. A few weeks ago my husband managed to get through to an agent who promised that a technician would come out and inspect our line, the tech did arrive as per our domestic helper. He told her that there was nothing wrong with the line. No note, or reference document name of tech was left at our home, so we have no reference to call back and ask what happened. We still have an unstable line, with long periods of not being able to use the internet. We get warnings on our home computers, cell phone warnings that our wifi is unstable still. my husband uses the internet as a working tool and is unable to work at home currently due to this problem. I am going to have to resort to urgent measures such as stopping the payment to Telkom as we are paying R1800 plus a month for something that is unreliable and doesn't work properly.