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Also, if you've been penalized in Google Maps, your listing might abruptly drop down to zero traffic levels. You should do some typical searches where your listing was appearing, and see if it's still showing up in the search results.
If you think you have been penalized, you should revise your LBC business profile to match up with their quality guidelines. Google LBC recently revised their quality guidelines, becoming slightly more conservative in what is and is not allowed.