Fair and Foul

[3ump]

Need some good advice here, during 17 year old tournament game. A long shot down left field line FAIR by 3 feet I was on the plate. I focused on ball landing and it was FAIR, I immediately gave signal for fair ball pointing in 3 times. As I look into the infield my partner for whatever reason throws his arms up and calls foul ball, while his back is to me. There was a runner on 2nd and he was going on the pitch .
Needless to say all hell broke loose it was a tight game. So the settlement was as follows, runner on 2nd I allowed to score he was around 3rd before the foul call. Batter I sent back to first because the only reason he was tug out was the fact foul was called and he stopped to go back. Partner claimed he heard someone call foul but never turned to see who and I have a very loud voice. He also said with more chalk on line he would have seen where ball was.
Long story short what do you do when this happens? Was my placing of runners right or does foul over rule?????