What is your broadband solution? and with whom?
FTTP, or below?
I joined the local authority-backed scheme and, since early this year, I have FTTP with OpenInfra, a Swedish Company. Before that, I was with BT.
Now, here's the strange thing. I have been waiting for OpenInfra to bill me, so I could stop the BT contract, but they haven't. I phoned them and they said, we're not due to bill you until July 24. Well, I said, who is providing me with broadband now? They checked and said "It's us – we'll cut you off". I said, "No, just bill me". "OK", they said.
Nothing heard since....
Well your number 'should' be separateable from the broadband then....IF they support and are willing to do so. Sounds like that may be an issue. Esp after looking at their website.
Or just start again with voip on a new number, esp if theres billing issues, removing any voice from the contract could be awkward.
Essentially you'd have to ask if you can migrate the voice number away and keep the service....then you can work out where to go for that.