How do i get a confirmation from Apple, about one canceled payment.

I bought an application, from my card account was charged amount and after 5 minutes I asked to cancel subscription and to refund money to my credit card. Apple support has approved my request but steel this amount is blocked on my account. So, i called support center to my financial institution, but they told me that i need a confirmation from apple that they have canceled this payment so my bank could unblock this amount. Does anyone know how do i get this confirmation from Apples?