STARDOLL.COM? Anyone? Major Question!?

Hey, everyone, well i have a question regarding stardoll.com. well it's this fashion website that lets users buy virtual clothes for their virtual dolls, and dress up celebs. Well, recently, Ive noticed that some of my fave celebs to dress up are not on stardoll anymore, they kinda 'disappeared?'. ex: gwen stefaini, hayley williams, etc. have disappeared? anyone know why? thanks!