Poor problem solving.

I took out a Cell C LTE contract 3 weeks ago. My initial coverage was 2 bars on LTE and got speeds of 3 to 5Mbps. Then I got myself a outdoor antenna and my coverage went up to 5 bars with a -65dbm gain. Speeds was then hovering between 8 and 12 Mbps download.2 Weeks ago I contacted Cell C to enquire why my speeds was so low as this is a LTE contract. They then pointed to the fact that the closes base station was not a LTE site. I aligned my outdoor antenna to the closes LTE site and with my reception of 5 Bars and -65dbm I should be getting much more then 8 to 12mbps. They have informed me that a supervisor and network engineers would be contacting me and that never happened and we are 3 weeks later. On Saterday evening 09/04/2016 my speeds fell off a cliff. On a LTE contract I am getting speeds of 2Mbps download if I am lucky and again I am dealing with technical support and call centres. A simple solution would have been for them to come out and check the speeds in my area. It seems call centres are the closes I am gonna come to solving the problem. Why must certain areas get great speeds and my area get this low speeds without any explanation being given.I am a paying client.