Their father starts the blackmail again

Well, here we go. I was a bit short on the bills this month, so I called their father's mother to ask her if she can get hold of him to tell him I need money. At first she said she talked to him a couple of days ago, but within two minutes, she magically had him online on Yahoo msgr and told me that he said if I give her my kids birth certificates and social security numbers that she can give me