I've had a couple of people lately report to me that when they call my RingCentral number, they get a message that the number has been disconnected. Of course, these are people who also know how to reach me on my cell phone. I wonder how many other people are calling my RingCentral and getting the same disastrous result. One caller was local, the other was in another state. We are all in the U.S. One of the callers uses a VoIP system, the other a PRI. I'm not getting any help from RingCentral customer support.
Charles - a few things to check in this situation.
Make sure the bill is paid.
See if the issue is limited to a specific carrier (T-Mobile, AT&T, Verizon, etc.) If you can limit it down to the specific carrier then our team can open a case with that carrier to have them check the routing. You will want to document the test calls (Date, Time, Called (to), Called (from +carrier), result).