Duplicate contacts

I have duplicates in my contacts such as John Smith and Smith John. I have Cleanup Duplicates App but it didn't pick this up.

Does anyone have the answer?

Apologies if this is in the wrong section; very new to this!

Duplicates can occur if you list a contact as: "Last name first" and then again with "First name first". What you need to do is make sure that your contacts are consistent in the way you have them listed. As far as the dupes are concerned, just manually remove them. The Cleanup Duplicates App thinks the two entries above are different.