What to do?

So my sons grandparents have been trying to pressure his father to be in his life behind my back.

His step mom told me the other day when I was over, and said he just ignored them.

My sons 2 and a half, I have tried a million times to get him to be active in his life and I’ve given up. The last time was in October and he kept asking me inappropriate questions, I kept refusing him and told my SO and we cut it off. He didn’t even care for our son.

I just feel so disrespected for not being told about this decision that they made without me. They did this before too when he was a baby, they gave him 2% milk when I repeatedly said I wanted to wait until he was a year. They never listened to me and just told me that they raised kids before, they know what they’re doing.