Stop buying your kids stuff. I tell my kids every time they are up set with me in a parenting moment "You don't have to like it, you can even be mad at me, but It's my job to raise good people and sometimes that means doing things you don't want to do.
And it was after months of silence that I realised we make better strangers than we ever did anything else. A tough and harsh realization. but a good one to have instead of holding on to something that isn't good or meant for you.