Contacts "On My Mac" are missing

All of the Contacts "On My Mac" are gone. Attempted to log out of iCloud, followed (instructions to import -- save one contact to desktop, open *.vcf file) Then log back in to icloud. Just end up with dup contacts, PLUS unable to remove duplicates. Called Apple Support (for iMac, same issue as MBP), we fixed issue, all contacts "On My Mac" appeared, yet as soon as the support call ended and I re-opened Contacts, and only iCloud , google and Yahoo contacts remained. No "On My Mac" contacts! Tried to remove duplicates; waited a long time, but have to force quit each time I open the contacts. Help!