Three Home Broadband Dead Slow

I live in a London house-share and we took out a contract with Three for 4G home broadband earlier this year.

The download speeds are atrocious at all times, rarely above 5 or 6mbps, but often as slow as 1 or 2mbps. This makes it frustrating to download sizeable files, and streaming Netflix/Youtube or videoconferencing is often at very low quality.

We have placed the router (a Huawei B535-232) by a window as suggested and the signal quality is very good. We have also tried multiple locations around the house both upstairs and downstairs, but it doesn't actually make much if any difference.

I have Googled this and it sounds like the issue is Three's network suffering from extreme congestion; when I complained they promised that things would get better after they finished their 'big network build' on the 15th of this month but now that they have, it seems just as rubbish as before.

I am obviously very dissatisfied but are my expectations for a better internet service fair? My iPhone 11 for instance on giffgaff usually speedtests at 100mbps down so I will often tether, but this is not a permanent fix.

Edited by pbaran (Fri 16-Oct-20 20:40:06)

If giffgaff works well for you then a SIM on O2 or Giffgaff might be better than Three - Three could be down to congestion or just not getting a good enough signal in your house (despite the router saying the signal is strong).

have read on mobile phone forums that Three in London is indeed appalling.
hope you get something decent sorted soon, fingers crossed.