The CSA wash their hands of situations like this, even though they have the info on their website on what you can do! No-one told me about REMO for years, I stumbled upon it by accident looking for some different info for a friend on the CSA website.
If your child's father is resident in another country then you can try the REMO route. There is info regarding this on the CSA webpage, but they don't deal with it themselves.
Basically REMO (reciprocal enforcement of Maintenance Orders) is all done through the court. If you don't have an order in place the court will get in touch with the authorities in the country he resides in (if it's one of the reciprocating countries) and that country will calculate what he should be paying by their system and make an order. It can take some time for this process though. If there is already an order in place, or once you get one in place they can enforce it in the same way the CSA can take money directly from salary etc when people don't pay.
In the first instance you should contact your local court and ask them if they handle REMO cases and if not which is your local court for that. When you have the right court they will tell you what you need to put in your opening letter to them - ie your child's father is not paying any maintenace, and give a brief outline of the situation etc. They will then send you the application forms.
It doesn't cost you anything other than a phone call, some time writing your outline and then a postage stamp.
It's got to be worth a try, what do you have to loose afterall if he's paying nothing already?
And if he's sold a lot of properties that will have to be declared on his tax return whichever country he resides in. And if he completes a tax return the authorities there can calculate his income from that and make an assessment fairly quickly once they track him down from the info you supply them with. The more info you can provide the quicker and easier it will be for the authorities in his country of residence to track him down.
Give it a go
Gilly