I can't find magnet in my Kindom Hearts 2 game?

You get magnet after you beat Oogie Boogie in Halloween Town. You face him when you enter Christmas Town a second time(in the story). He is in the toy factory. In this battle Donald and Jack should be present. You will see 3 convayer belts. You can't get to Boogie directly. He is in a glass control box above the belts. You have to get presents and use reaction commands to get him down. Heartless and other harmful stuff will be there as well so be careful. When you get Boogie down (10 boxes) he is defenceless. Attack with all you got. Jack's Limit ability will bring him down with a considable amount of damage. When he goes back in the box, Oogie will change positions. In front of you should be lights. Those are teleporters. Blue means that they are active and pink means inactive. Repeat over and over again untill he is defeated. It will take time though. After the fight, Sora gains an ITEM SLOT, Donald and Jack receive MAX HP bonuses, and Goofy learns ONCE MORE. After a cutscene you get the MAGNET ELEMENT.

Hope it works.