Is it just a speed issue or are you seeing any "disconnections"? What Hub model do you have ? Can you put the Hub into modem mode and connect a GB enabled computer/laptop directly to the Hub with Cat5e/6 ethernet cable and test speeds like that ?
Meanwhile, check all your coax connections are in nice and "finger" tight at the Hub and wall box and at any splitters/attenuators/etc with no “unterminated loose ends, and that the internal wiring is ok with no kinking or chaffing. Also check that all looks good with the outside cabling and wall box.
If that’s all good.... Post up your Hub/network connection details and someone will check to see if there is a problem there. In your browser’s URL box type in http://192.168.0.1 (or http://192.168.100.1 - if in modem mode) and hit return. On the first page up [there should be no need to login if you have done so before] click on the “router status” icon at top right (SH2’s) or text at bottom-middle of first page up (Hub3) and then copy/paste 3 FULL sets of data onto here – from the Downstream, Upstream, & Network Logs pages. Don't worry too much about the formatting it can be easily read & DON’T include personal data or MAC addresses - blank them out - if you copy/paste the data, the board software will do this for you.
Also, may be worth setting up a free “Broadband Quality Monitor” to continually monitor the state of your connection and record any network dropouts. It does it 24/7/365 and it keeps a visual record of any/all of your network disconnections, useful data to have to match to the Network logs (in your Hub settings) and also in discussions with VM. Make sure you uncheck the “ignore ping from WAN side” box in the settings if you see a wall of "red" - note it will take an hour or two to start seeing a sensible picture.
Thanks for posting. My apologies for the broadband issues. I've ran a background check and can see that we do need a technician to visit the property as the service is experiencing a performance fault. I'll PM you now to arrange.