LTE very slow was 24mbps now it is 5mbps

When I took out the LTE smart broad band contract Telkom was advertising up to 100mbps When I got the it was giving me about 15mbps. Then only 7 months later Telkom came to install the antenna as this was part of the package. After this I got 38mbps to 45 mbps. Every month it declined. For the last few months I am only getting about 5mbps.

This is very slow As I took the uncapped package the mos expensive. And not getting the results,