Yep, in-app purchases aimed at kids is always a sensitive area

"sensitive" undersells it. Apple in its refund form has an option to select "unauthorised in-app purchase by a minor" as the reason.

I was not aware how predatory this market has become until an annual subscription after a "one week trial" renewed itself automatically despite having been already cancelled on the last day.

I'm assuming the money is lost because third party subscriptions might require earlier cancellation, but that was the last time I allowed for anything with such a short trial period.