Useless service

Good day. Can you please urgently advise on the status of complaint ***. My parents had their Telkom line replaced with this useless wifi box that has been faulty since the day it was installed months ago. They reported the above fault and were told that it will be replaced within 2-3 weeks and till today no one has bothered to call them or replace the unit. A gentleman by the name of Ringo installed the unit and gave them he's telephone number *** to call him if they have any problems. But, it seems like he never answers he's telephone. My parents live in Finsbury, Randfontein and are very elderly and need their telephone working correctly in case of an emergency. The telephone line keeps on going dead and they have to switch the wifi box off and reset the line to get it working again. I find this completely unacceptable as they were told this would be an improvement of their service. But it is completely the opposite. Why must they be paying for a service that is so pathetic. Please advise urgently as this has been going on for far to long now, and when they call into the service centre and quote the complaint ref number they keep on been told that the issue is with the technical dept but nothing is getting done. A Prinsloo.