9MBs speed on 100MBs line

I have ordered and paying for a 100MBs fibre line from supersonic. I am getting around 9MBs upload and 7MBs . I engaged with Luzane and she told me I should perform a speed test which I did perform. She told me I need to connect and test with a Lan cable to the router, apparently the engineers at MTN/Supersonic will only act on the issue if there a results from the LAN cable. The only devices, I have in the house with a LAN connection points are large TVS (55inch) that are installed on the wall and cannot remove them to perform a test. The newer laptops do not have LAN connection ports.