I used to work for a cell phone carrier and people would call in all the time not knowing their pin. They would get upset when I would tell them I could not release any information about their account until they knew it.
They got even more upset when I told them if they could not call back with the correct pin that they would have to do a sim pin unlock, which was a long and tedious process. I do not think some people realized that the sim pin is in place to protect them. All I can say is when you get your phone and you set up your pin, write it down in a safe location.