poor service

I ordered the 1 gig sim from rain. Their activation and delivery was super fast. I stay in Cullinan, and with the 1 gig package I got up to 11 mbs, so I decided to upgrade to the R479 package uncapped, but ever since I upgraded, I only get 3 mbs! I have submitted many queries on their site but have not received any response! I have about 5 ref nr for queries submitted to them but they do not respond! One of the service personnel helped me but left me stranded in the middle of the setup!