What should i do or who do i tell? help!!!!!!!!!!!!!!!!!!!!!?

Take her to court, you have an easy open and shut case. She is a drug abuser who while in her care, your stepchild has suffered educationally and god knows what else. You'll win. It won't even take long to do this. Visit a lawyer, get a court hearing or judge to sign petition and you have primary care. That child support could be going to her alcohol and drug abuse rather than feeding and clothing stepchild. Help the child, she obviously needs it.