Any step parents ?

So I need some advice on how to go about making my relationship a priority and making my opinion heard/matter if I’m helping him raise his child ?

I’ve tried to be on good terms with the child’s mother but she is constantly on social media bashing me or texting my bf talking crap about me. And I don’t feel as though he makes me a priority in our relationship or values/take into consideration how I teach or am help raising his child on our end. Given she is with me most of the time. I’ve been in her life since she was 8months and she is now 2. He also doesn’t like that she calls me mom. When I try and correct her and tell her my name she ignores me and continues to call me mom. But calls everyone else by their names . I’m soo lost and confused on how to deal with all this