I don't understand, earlier this week I got a margin...

I don't understand, earlier this week I got a margin call. I was trading gold and I am pretty sure I was in a profitable position. When I realize I got a margin call I was so surprised. So I checked what was going on and I realize that the price is not the standard price as other brokers. Why is the price not the same as another broker's? Also, I did place a pending order and a stop-loss order but it did not trigger. Was it my fault? I am pretty sure I placed it, I always did every time I open a position.