i did not authorise my purchase.

Hello, dear support Apple, I had a problem. Now I will describe everything in more detail. I have a younger sister, she is 4 years old. She once asked me to buy her a paid subscription to the VC music, said that they would charge me $ 4 and that's it. I gave her my card details and on March 21 I was charged $ 3.99. After that, I did not use my card because there was no money on it. Yesterday I put money on my card to go today and buy a gift for my friend’s birthday. When I woke up, I saw a notice that $ 3.99 was removed from my card for something. I was at a loss and thought that hackers had hacked my card. After that, I jumped in my sister's phone settings, and found that the subscription my sister purchased is renewed automatically, and the money is withdrawn from my card. We both did not know this, my sister cries and apologizes because she feels guilty. Dear Apple support, I hope for your loyalty, this will not happen again. Please return the money, we are from a poor family and every cent is important to us and we cannot allow unauthorized expenses.