This support page provides several support contacts.
My Business API team
Contact the Google My Business support team for technical support.
Answers to non-API questions about Google My Business can be found in the Google My Business Help Center.
My Business community
Visit the My Business forum for discussions with developers and members of the My Business community. To ensure that your questions are quickly addressed, preface the title of your post with "[API]".
Tutorials and FAQ
Visit the Google My Business Help Center for tutorials on how to use Google My Business and answers to frequently asked questions.
For information on how your Google My Business account syncs with Google Ads, see Location extensions.
For general information and to learn more about the Google Ads API, visit the Google Ads API developer site or the Google Ads API forum.