- First, eliminate duplicates by visiting https://contacts.google.com/suggestions from a desktop computer, as the "Merge All" button doesn't appear on the mobile web.
- Complete the merge
- To eliminate the same duplicates from iPhone, sync again using this app, making sure that the "Sync Deleted Contacts" setting is turned on
This help article relates to the iPhone app called "Contacts Sync" which can be downloaded here:
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