Completely hosed my Google Contacts

I bought this app, and left it to do a 2-way sync. My phone started to show duplicated entries all over the place. Alas, I was out of town while the sync ran, so I couldn’t get to my Mac to turn it off. On my iPhone I found 28 copies of each contact that was in Google. Once I got home and turned this software off, my Mac contacts had 28,000 duplicated records. Icloud, Facebook and LinkedIn contacts seem to be OK, but Google has thousands of dupes I now have to figure out how to get rid of.

Hook, Slice & Shanker about Contacts Sync for Google Gmail, v6.5.2