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Perfect. I updated my preferences.  I'll let you know when I hear back from Google on this.

A great option for service area businesses to rank well organically in other towns is to utilize a service like NearbyNow.  They create real content that isn't just you're typical keyword-stuffed service area pages and they rank really well if you utilize the tool properly.

Also now that ads are in the 3-pack everywhere on mobile, I'm suggesting that to clients as well.

You were correct in your assumption on virtual offices - they are not allowed: http://www.sterlingsky.ca/google-updates-gmb-guidelines-virtual-offices-not-allowed-sabs/

If it's just submitting new listings and not NAP cleanup you could hire Whitespark to submit them: https://whitespark.ca/citation-building-submission-service/#prices

In order to provide advice, I'd need to know the website and the search term you're looking at.  Can you provide those?

Ben,

If your goal is to replace every single phone number online with the tracking number, that's fine.  In my experience it is almost impossible to keep the old phone number from re-populating since it's published in offline sources (like the phone book).

What I was recommending would be good if you wanted to isolate/track JUST the calls from GMB.

Tom Waddington (one of the smartest people I know) pointed out, most of the spammy backlinks are pointing to a domain (reliant-plumbing.com) that is redirecting to your site.  Why don't you kill that domain (make it 404) and see if it fixes this?