I want to demand for child support or I would cut off their visitation
How do you plan on demanding child support and threatening him to cut off their visitation?
First, by telling my soon to be ex "If you want to see your kid's face, pay $250 a week"
I think that it's necessary for the other parents who provide child support, so I think it's very appropriate for you to demand payment when necessary. However I don't think that it is appropriate for you to threaten them to cut off visitation if they are not able to pay. I recommend that you go to the proper channels legally to see what you can do about them paying their share.
But I want them to suffer my wrath.
It is not about your ex feeling your wrath, it should be about the child. You should just tell him that the support is going to be for the child and he should have no problem paying it. You are both the parents here.