Hello & Welcome to Just Answer,
Sorry to hear of any issue you may be having with your device(s).
May I ask:
1) What is the AGE of the 2789?
2) Did the update of the 2789 appear to "go well" (no errors or warnings)?
3) HOW LONG has the 2789 been powered up - after the update?
4) One the MAIN SCREEN of the 2789, can you see ANY "signal bars" at the top left of the screen? If so, are ANY of the bars GREEN?