Ok. I learned the details of playing with same code. You need both code and steam account. Once you activated the game you should go offline so more than one player can play in same time.
Normally it should have come even before the original. There is a rumour about that sigames paid off reloaded, razor etc. to delay crack and increase their sales.
It didn't work. It gives duplicate product code warning. It was working for previous versions, it seems sigames fucked it up too. Thanks again those who wanted to help.