Worst Telkom service

Telkom has replaced my copper line with wireless. After replacement, we are barely getting 1 mb but paying for 10mb line. When I called them they keep reroute my calls to new person without resolution, each time when they route call I should wait minimum of 30 minutes to answer my call. What options do I have? Can I file a case as they are not giving me what have been promised but charging me for 10 mb line