What happened to Sonny with a Chance? So Random?

Okay well there's no new episodes and now they come out with this new show called So Random and Sonny (Demi) isn't even in it? Did Sonny with a Chance get cancelled? If so why? And if it did why isn't Sonny in So Random? It's like they replaced Demi with Sterling Knight (Chad) I mean, did Demi quit or something or went off to do a new show? And they made So Random because Sonny with a Chance is all about Demi (Sonny) Please answer I'm curious? :D