What are they thinking???

Greetings!

I'd left my previous company a month ago. A week back, the HR personnel call me up, asking me to collect the pay cheque. However, he mentioned that SGD698 had to be deducted from my salary because they found a retail Vista Ultimate DVD is missing (only the DVD, original serial key and license still attached to the retail box), which is under my care previously.

I mentioned that i'd no idea how come it gone missing. if it's my fault, i'm ready to compensate the missing cd (which i plan to download the trial version and burn it to DVD, they can key in the original serial key during installation, anyway; or i can ask Microsoft to send me a copy by postal also, which cost around SGD40). But definately i'm not going to pay SGD698.

If they insist to deduct those amount, which party should i contact in order to show them what is the right way in doing things?

Regards,
Tyrl
Singapore