'New' Sky hub not working

Hi

I am a 'newbie' so please go easy on me please !

I have had Sky internet for a very long time. The original white router 'died' a year ago so my neighbour gave me her redundant SAGEM unit which was even older than the original one but just plugged it in and away it went, the wireless signal is weaker but was acceptable...for a while.

I have been given a white (still boxed) Sky hub router part code 14951(Z Sky hub ?) when plugged in it tells me I have a connection problem between it and the phone line, it seems I need an Openreach modem.

My phone lie comes in through a BT openreach socket and uses ADSL connectors on to the Sky box and SAGEM router.

What is my next move to get the 'new' hub working ?

Thanks for any help.