When VM connections work properly they deliver slightly above the headline speed and do that consistently at all times of day. Sounds from the contributions from @Jonny-M and @jbrennand like the laptop itself is limited to a nominal 100 Mbps (about 94 Mbps maximum as measured by a speed test), but the 20-70 Mbps speeds are worrying and should not be down to the network adaptor. What speeds are you seeing on a mobile phone? You may need to download the Ookla Spedtest app and run that repeatedly. If those speeds are all 200-220 Mbps consistently then the connection is good, and sounds like a laptop problem.
If speeds on a phone are occasionally low and erratic, then although wifi speeds can vary, combining with the laptop speed range it points firmly towards a faulty broadband connection. That stuff you were told about "monitored for 30 days", I suspect that's crap, and whilst VM can set up speed checking, I doubt they've done that for a new customer via first line support. We're used to reading reports here of the offshore customer service staff making it up as they go along to end or disconnect calls.
Most speed faults can be resolved, so if your other options are unacceptably slow then you may wish to persevere with VM, although as you've found, VM support is often appalling, so with your 14 day cooling off period ending in about a week, choose wisely. After that you're locked in for another 18 months.
