Unauthorised Hint Subscription And I Need A Full Refund

I am writing regarding an unauthorized subscription and payment that has occurred through the Hint app via the Australian iPhone App Store. A short time ago (a little over an hour before writing this), I received a notification from my banking app that a payment had been taken, and I saw that, after using the remaining small balance in my PayPal account, approximately $45 was withdrawn from my linked savings account to complete a $48.99 charge for Hint. I did not knowingly approve or agree to this subscription and I was not aware that any payment of $48.99 would be taken. As soon as I realised, I tried to contact Hint support, but so far I have not received any response from them. This situation is very concerning for me because the payment was taken without my clear consent and directly affected my savings. I request that the unauthorized subscription be cancelled immediately and that I receive a full refund of $48.99. In addition, I want my stored payment details to be removed from your system and I would like written confirmation that the subscription is cancelled, my payment information has been deleted, and that such an unauthorized charge will not happen again.