BYOP Voice Connectivity Problems

I went to an At&t store tonight and had an At&t branded LG V35 ThinQ  (BYOP) activated on a new sim card they provided and a prepaid service/data plan.  Everything was fine, she made a test call to the store it worked.  Data worked Great.  I get home and data still works, text still works but i go to call it never connects to make the call it just ends the call.?  Not sure why it would work there and not even out around my place because i went for a cruise to make sure it wasnt bad service but nope still no voice connection.