My familys torn apart what do i do HELP!!!?

okay my uncle pat has a new wife who has slandered my mom on the internet for no reason. My uncle has two daughters from another woman so she hasn'tt adopted them or nothing. And they have totally cut the biological mom out and she doesn'tt get to see the kids. But haven'tnt seen my cousin erin since may and i miss her, we are like sistersChristmas is coming up and i hope to see her. What should I do in the meantime?