The hub ‘name’ and password are for wireless devices (WiFi) so IPads ,tablets , mobile phones etc , the telephone service doesn’t use WiFi , and if you have a wired PC for example ( so connected with an Ethernet cable to one of the Ethernet ports on the router ) then the WiFi name and password are irrelevant, you also must have something else ( that you referred to as a router in another room ) if this is a wired WiFi extension then it probably has its own WiFi name and password and that stays the same , so changing the router in your case will only be an issue if you try to connect directly to it via WiFi , in which case you need its own WiFi name and password .
Why didn’t you mention the fact you were supplied with a new router and this other ‘device’ existed initially, if you had the advice you were given would have been more helpful
