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You would only be able to use another hotspot, not the one from your own home hub, until your broadband has been activated. So if you do already have your home hub, then leave it turned off.
On the Android phone, "forget" any stored wireless networks which are anything to do with the free BT Wifi hotspots, as there are usually quite a few "remembered" ones.
Then try again to re-connect to the one you want to use. Sometimes this fixes the problem, as there are often to many "remembered" ones, with the same SSID.
This may also help on other devices.
Is it just one particular hotspot that you can't connect to or none?
Sounds like it is a problem with the hotspot rather than your devices. Unfortunately, nothing you can do about that.