U should never have called her and informed her of the kittens. Moreover, u should not have sent the pics of the kittens to her. Now she has evidence about the kitten.
In Contracts class, we learned a classic case that is very similar to this. The result is: because the seller did not know the cow was pregnant when he sold it, and because he planned to sell a barren cow but a pregnant cow was delivered, the contract was invalid on the ground of mutual mistake. Therefore, the breeder has the right to take back both the mother cat and the kittens and refund you.
Now u might have to listen to her and keep one of the kittens.
