Google has been sending out email notices to Google My Business users that their unpublished business profiles will be deleted within 30 days. Most of the time this is fine, but if you do not want your unpublished listing to be deleted, then you must verify the listing within 30 days.
The email subject line says "In 30 days, your unpublished Business Profile will be deleted." The body of the email says "Keep your Business Profile." Then it says "In 30 days, the unpublished Business Profile for [Name - Address] will be deleted from your Google My Business account. To keep your profile, simply verify your business today."
In my case, this is my old office location from 10 years ago, here is the email I received:
As Carrie Hill said in the Local Search Forums "Don't panic - these listings that you may have created but never published. Most of the time, you'll notice that the email came to a different Gmail address than the one that "owns" your verified listing - we've all started creating a listing only to figure out we're logged into the wrong account."
Forum discussion at Local Search Forums.