Google recently added the ability to restore your contacts through the desktop version of Gmail. This update functions similar to a system restore, in which users are able to roll back changes to their contact lists to previous dates (up to 30 days back).
“Let’s say you accidentally deleted a bunch of contacts or wiped the contact data from your Gmail account by mistake while syncing to another device. Visit Gmail’s Contacts section, select “Restore contacts” in the “More actions” menu, and choose the time you would like to revert to.”
(via Google)
