I don't know if this is the same thing, but I have a Used Car Dealer that had the 'Product' post type available for a long time. I have listed several cars as products, and they showed up in Google Maps under a 'Products' tab.
In the last week or two the 'product' post type is no longer available. And, in Google Maps, that tab no longer shows either.
New advertising option:
A review of your product or service posted by a Sterling Sky employee. This will also be shared on the Sterling Sky & LSF Twitter accounts, our Facebook group, LinkedIn, and both newsletters.