Most likely someone entered their phone number incorrectly and is now upset the code did not come thru.
But you can always open your return and look at the log in history to see if someone tried to access the account ...·
Log in and go to your 2018 Tax Timeline....scroll down to Add a
State." (you don't really add one; that's just to get the return
to open up.)..... Click Account Tools, then Security, then scroll
down for access history.