Tough family situation please help

Hi guys. I’m 16, I don’t know who to go to for this.

Basically my mom is married to my dad, (he is in prison for 240 years Bc he is a child molestor and did things to me and my sister) my family doesn’t know he did things to me.

He is a veteran, and my mom is only married to him because she gets $900 for her, $900 for me, and $900 for my sister monthly from the veterans association.

But In order for him to not divorce her, (she will lose the $2700 a month if he does) I have to talk with him. I sometimes miss his calls and don’t write often. It’s really emotionally draining me and I hate communicating with him ☹️ my mom has told me I can stop anytime. Today I told her I no longer want to talk with him. She got really mad and said we were going to struggle again and things would get really hard. She said it wouldn’t be my fault but I need to really think

Now idk what to do

I am tired of talking to the man that sexually abused me from the age of 5 until I was 12. What would you do?