key fob on my vauxhall?

my key fob has had a battery replaced last week and its not working but after a closer look there is a piece of card in the key fob holding the battery in place as loose connection. it hasnt worked for 2 days but works today. when i rang vauxhall they said i need a new key fob - do i have to get it sync'd to my car ?

a new key fob and sync will cost £100.

and there going on about a car pass, havent been given one but they can get one from vauxhall for £22, do i need this or can they get the details from the chassis.

HELP PLEASE