Does Google offer a support number for the Android OS as a whole? If not, why?
No, Google does not provide a general service support number. Google provides the base Android operating system with components like a contacts manager. Both the phone manufacturer and the service provider may customize the OS, use their own applications, or replace stock applications like the contacts manager. Google is not able to support these customizations. 

In the US, I would expect the best tech support service to be from your carrier at local stores. They are the ones with dedicated personnel who can physically touch your phone and show you how to do things.