Confusion on the bases...

[McMac]

Let me start this by saying, I am not a softball umpire, but I am a basketball and football official. I was playing in my church league game tonight and this happened. Rules set: USSSA

Situation: 2 umpires, BU is behind 2nd. 1 out. R1 at first, Batter hits fly ball to LF down the line. F7 makes play on the line and drops the ball in foul territory. PU puts right arm out at about 45 degree angle (not knowing if he is calling fair/foul). He never says foul. R1 advanced to 2nd on assumption that it was fair, BR goes to first. As told to me, BU called it foul. I here PU call time when the ball had reached back into the infield.

So R1 began to retreat to 1st in thinking that it was now a foul ball. BR began walking back down 1st base line. F1 then throws ball to 2nd and tags bag. BU calls him out. BR made it back to 1st before any tag applied.

In all discussion between umpires, they ruled it was a fair ball, no one called time, no one called foul. So R1 is out for abandonment of the base.

Is this correct? Is there any way in the confusion that the runner could be put back on the base?

Thanks for any help!