I accidentally deleted my contact list. How do I retrieve them?

If you were syncing Contacts with iCloud, go to iCloud.com using a browser, then Account Settings, and look under Advanced in the lower left hand corner. Click Restore Contacts. If you weren't syncing Contacts, do you have a backup you can restore from? Restoring from a backup erases all data currently on your device. Any data newer than when the backup was made will be erased. A restore is an all or nothing restore. You can't access a backup to see the contents and only restore certain files.

Backup - Restore your device from an iCloud or iTunes backup.    *