Refund My Unauthorized NetShort Subscription Charges After Apple Cancellation

I have a problem with an unwanted ongoing subscription charge related to the “Try” service provided via Netstory Pte Ltd on my iPad. I cancelled the subscription through Apple, and in my subscription history it clearly shows that the subscription was cancelled on June 11. Despite this, I was still charged again on July 16 for a weekly subscription fee of 29.99. I request a full refund of all charges made after the cancellation shown on June 11 and written confirmation that my subscription has been fully cancelled so that no further payments will be taken.