Another Birth Control Bill - is the ex clueless or hoping?

We received ANOTHER new bill for my adult stepdaughter's birth control from my husband's ex-girlfriend.  I am wondering how many more times the ex is going to send us the monthly birth control bill for my adult stepdaughter, who we have no legal obligation to pay support for, let alone pay for her birth control - $60 per month - before she gets a clue! 

Even if child support was still ordered paid on my stepdaughter, which it isn't, birth control would never be a legal obligation.