MTN Fibre (SuperSonic) 100mbps Fibre Connection is giving only 5mbps speed -

We have taken MTN Fibre connection few days ago for 100 mbps download and upload. but internet is very slow and poor. when done speed test it hardly giving 4 - 5 mpbs. This very poor internet connection. It is slower than 3G connection. Super Sonic is behind MTN Fibre Servies. I am disappointed with this. Hence, I request MTN Fibre to kindly cancel my connection without any charges and take away their router and Vuma Box. I am not happy.