Please don’t think that this was a FU. You taught her valuable skills and empowered her to get out of a situation where she was very likely unsafe. And now the authorities are involved whereas they wouldn’t have been before.

The mother is trying to blame you because it’s actually their fault, not yours. Just think if you hadn’t taught her those skills. If she had still escaped, she would have been even more unprepared or maybe stayed in a more urban setting which can be also very dangerous.