LTE slow speed since I received the the LTE cell C

I stay near the east rand mall in boksburg I purchased a Cell C sim card and LTE router after verifying that I fall within a LTE area with Webafrica. I put the simcard in my LTE router, and the device shows that the network is running on LTE/4G 3 bars on the router.

I did a speedtest, the download speed is on average is 1.31Mbps. This is slower than Vodacom 3g! This is also not the "speeds up to 20Mbps" average customer as advertised

I used to have 4meg adsl which was faster I have this router for 2 months now with the same issue of slow internet speed and am thinking of switching and thowing the the cell c sim in the dustbin