Mom trying to force me to have a relationship with " dad "?

To me, I don't have a dad. I don't have a father. But my mom is trying to get to spend time with a guy, who treated her like ish. ad never did anything for me. And he has like 10 other kids. He has never really done anything for me & i don't like him & feel uncomfortable around him. And he calls my mom asking about me & i feel like she is going to try to force me to spend,time with him. And he's a creepy perv. i dont want too :( what should i tell her?