Faulty sky card

Hi, I had sky installed 4 weeks ago, we requested multi room which never worked from the start. We were told that the card was faulty and they would send a new one out which i have just rcvd today! Still no joy so we called the number provided on the screen to be told that we need to leave the old card in the box for 24 hours then insert the new card and it should be working fine. Nobody has given us an explanation from the start?!?
Thank you