Can you log into the hub over a wired connection and check the network status and power levels?
How is the landline connected - is it using VoIP - phone socket comes directly from the hub (on a short US to UK adapter lead) ?
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I know a bit about Wi-Fi, Telecoms, and TV as I used to do it for a living but I'm not perfect so don't beat me up... If you make things you make mistakes!