If your contacts are gone from your device, there is no on-device recovery. Rather, restoration from the regular and complete backups you perform would be needed...you can find instructions via the Backup link in my auto-sig on this post. Or, if you are synchronizing with a desktop PIM, then they should be safely there, ready to re-sync.
If you have no backup from which to restore, then this old saying applies to you: "There are two kinds of computing device users: those who have lost data, and those who will". Backups, quite simply, are neither a reactive nor an optional activity.
Occam's Razor nearly always applies when troubleshooting technology issues!
New to the Community? Click here and also here for helpful guidance. Also please click here for additional helpful information to guide you as you proceed. I always recommend that you treat your BlackBerry like any other computing device, including using a regular backup schedule...click here for an article with instructions. If anyone has been helpful to you, please show your appreciation by clicking the button. Need a reference to BB10 OS/SR versions? Click here. Need a specific BB10 AutoLoader? Send me a private message.