Terrible service and network speeds

Hi I've been struggling with really slow speed in my area kempton park alot of the time it in kilobits. When we first got the package it was running at 20-30mbps now it's barely running you cant even load a web page in a hurry. We've been complaining to mtn for 3 months now and each time we receive no help or get told a manager or person who can assist will phone back but we've been told this several times and not once have received a call back what is the point of spending R1000 on a data package if it dosnt work. Honestly shockingly bad service