Unfortunately, the ad networks are refusing to reveal the identity of the scammers so that legal action can be taken. Why are the ad networks so keen to protect the identity of the scammer?
Ahem. Not to be rude but - but where are you living? In 19th century Dodge City were people take the law in their own hands?
It is simply illegal for businesses to disclose any information to third parties without a court order or a request from law enforcement authorities.
If I called you and said - some user of your service is violating my rights, please give me his name and address - would you comply? And risk getting sued for breach of privacy laws - and if the request was simple social engineering to get personal information - be liable for the damage that has been caused by you disclosing the information? I think not.
So if you want the information you have no choice to either get a court order yourself or to involve the proper authorities.
Or forget about it. Nobody in his right mind will ever disclose such information to you just because your requested it.
You are simply doing it the wrong way: First you have to take legal action, then the networks will have to disclose the information, then you can go after the scammer.