Just updated phone - all contacts have been deleted. HELP! I need these numbers please

Contacts are designed to be synced to a supported application on the computer or a cloud service.

Simply sync them back to the device.

Alternatively, you can try restoring the device from the backup that was created prior to the upgrade to see if that helps.

also sometimes the contacts are not deleted they simple need time to be pulled down from the cloud, might i suggest simply waiting a while to see if your contacts 'appear'? if all else fails i would take diesel vdub's advice and do a hardwire sync up or restore.