Refund subscription

On June 20, the apple took 37.01$(Photo Grid) from my Bank Account BOFA.

As soon as I know the transaction, I unsubscribe and request refund from the apple.

In the subscription list, it was already unsubscribed but I didn’t get any refund to my account.

how long does it take to get refund ?

I would like to request apple to refund ASAP.