Good question. I think this could use some discussion. Certainly a good call to hit a provisional. In related news, I had a similar situation in single man match play when my ball was not found, general public in the area, and 2 other ball were found. I chose to concede the hole instead of going back to hit #3.
My knee-jerk reaction is that your playing partners could not grant relief due to it being a stroke play event. Match play, they could.