Tell him to p!ss off. Leave it to the CSA to sort it out, don't give this another thought.
For a start he isn't going to start formal custody arrangements because he has already established he can't be arsed seeing your son - and if he does, well the little fella benefits from seeing his dad on a 'formal' basis.
FFS! You are forgetting your penis-attached-to-head visualisations aren't you?
And
WOO HOO!! for more child support - you both deserve it.xoxoxo
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