Someone spent all our money and it got saved

Me and my 2 public friends just started our saved public server and some mf joined, spent 1500 credits to artifice then changed direction to march and left. We re-entered and enerything was lost, our 1500 to wind, we had to go to march. Why were those actions saved was that a cheater? Can I do something to return our previous saved world, we were going to beat very high quota now it is ruined.