Google offers limited phone technical support for Android at 855-836-3987, but help with built-in accessibility features is hit-and-miss. They do offer a Explore by Touch tutorial.
At this time there are no books detailing Android accessibility, but there are many websites, podcasts, and other online resources to help take up the slack.
Websites
This excellent blog from Access Ana features a wealth of Android accessibility posts and directories of online resources, videos, podcasts and other resources to assist Android accessibility users of all levels.
This blog, maintained by J.J. Meddaugh, is an invaluable resource for finding and learning how to use accessible third-party Android apps.
Podcasts
A must-listen podcast from Serotek for users of Android accessibility. Listen to individual episodes on the website, or follow the instructions to subscribe and receive new episodes automatically.
Android from an Accessible Point of View
Takes an in-depth look at all things Android of interest to users of Talkback. Topics include Android gestures and apps that are both accessible and not at all accessible using Android.
Carrier Support
If you are using an Android phone, you may be able to obtain technical support from your cell service provider. Learn more about this in the final section of this guide, Accessibility Assistance from Mobile Carriers.