If the BB is wiped, the BB is wiped. There is no way to retrieve your contacts from the BB itself. However, if you were doing routine backups, you can restore your contacts (and all your other settings and PIM data) from the backup.
If you weren't doing routine backups, you can sync to Outlook and/or Google and/or Yahoo if your contacts are on those systems.
If you weren't doing routine backups AND you don't have your contacts on one of the above systems, then I think you're out of luck.
Use this as a lesson to never leave your data without a proper backup.