Poor Telkom ADSL service... Not working

I'm writing on behalf of my parents Telkom Internet. They got adsl in December 2018. Since day one they only get speeds of 0.3 - 0.5 mbps. They pay for a 4mbps line. A technician came out after numerous calls to Telkom. That day the speeds will be 3.5mbps. The next day back to 0.3mbps. This has been going on from December until now. The tech has been there on numerous occasions. It will work for that day and no more. Can Telkom please come and sort this out once and for all! The line number is ********** 110 Alexander Bay Northern Cape