I had a flakey service with VM when I moved to the Gig 1 service, random packet loss - resetting router would resolve it for a few days then it came back, games would freeze , video calls would freeze, everytime a reboot of router sorted it.
Had a replacement router, and 2 engineers telling me everything was fine (speed) which it was.
I got out of the contract only a few months in.
Make sure to set up a BQM here to show them the quality of the connection.