Any man who doesn't meet his responsibilities in paying for children he has fathered is an utter ******* ******* and, in my opinion, deserves all he gets.
You expect chavs not to face up to their responsibilities, being the stinking scum buckets they are, but a bloke that can afford a couple of Porsches in just over a year clearly (unless it is all a front) is wedged enough to pay for his kids.
Perhaps it is not wise to openly trash his car, but a couple of bottles of brake fluid on the paint work at 3am one morning, whilst not being obvious it is you, would give you an enormous amount of satisfaction.