I mailed a check to my electric company to pay my bill, but presumably it got lost in the mail because they never received it. I told them they owed me $ to cancel the lost check. They laughed then billed me for late payment.
Ok, that was a fictional story, but the point is the electric company’s response was appropriate. They’re not responsible for my lost check. And neither should you be responsible for your ad network’s lost check.
EDIT: Sorry for saying basically the same thing as my last post. It just seems so absurd to me that they would charge a fee for a screwup that happened on their end.