i can only offer opinion but that is the tech is wrong or maybe has not explained it well - you can check the speed that VM have the line set at - access the hub go to config and look at the speed setting
if thats 100 the config is correct - how are you speed testing - you need to test with a wired pc/laptop if you are testing by wifi then any speed is possible
as well as the confi settings post some more info
log into hub3 - 192.168.0.1 [or 192.168.100.1 if in modem mode] - DON'T SIGN IN, click - click router status [centre of screen] - and post the downstream and upstream figures - to see those press on the grey buttons/boxes labelled - upstream - downstream
if its an earlier hub button is top right
as to the wiring - there may be problems with it but techs [today] will nor drill through walls - to get from A to B apart from the external wall - they will not go under floors to get round a door fram but over the frame - so whilst you have wire through walls new wires though the same wall may only happen if you drill the holes
the tech offered a solution within what he is allowed to do - you should contact the landlord or owner to see if permission can be given
but lets look at the figures and see whats what - and further confirm how you are testing the speed
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Tony