Here is a reply from a VW CS regarding the same question a few months back:
Click this link Backup Assistant (sign in) to check if contacts are available. You may sync directly from the site, by simply clicking sync on the right hand side (above contacts).
You may also try to sync by adding your G-mail account to the your device then go to Settings > Accounts & Sync > Ensure Sync is on for G-mail account. You may also select Auto-sync.
For additional information on how to restore contacts, click the link below:
Backup Assistant