Paying for 10mbs only receiving 4mb for 2months

I am really frustrated with Telkom internet service. I have been complaining about my line speed since I upgraded in October. Fault numbers ********** 3. ********** 3. ********** 4. ********** 0. I'm paying for a 10mb line and only received 4mb. Telkom keeps saying that the line speed is over 10mb. A technician came out and said the filter was faulty and I must plug it straight into the wall and will be sorted. Nothing happened. Another technician came out and said they had reset the the line and speed test was fine for 1 day then went back to 4mb. So it's possible so don't know why it's not being sorted out. After numerous calls and reference numbers can someone please look into this. I cannot be calling continuously. If u can't provide what you are selling please tell us so we can look at alternatives.