roof bars

hi i have an astra mk3 5 door, when i bought it the roof rack was already installed on the roof (genuine vauxhall) i have a key to the roof rack but when i insert the key it doesnt seem to turn nor left nor right. last case scenario the key that came with it may be the wrong key. i really want...

ive seen a lot of modded estates on google that have chrome roof bars, any1 know where these can be bought from or is it possible to get the originals chromed???