PicsArt Charged Me $21 With No Warning After My Free Trial Ended

I started a free trial on the PicsArt app through the App Store. However, I never received any warning, reminder, or notification about the trial period ending, and once the trial ended, a charge was made directly without my consent.
On 07/01/2026, I saw that approximately $21 had been charged from my account. After noticing this transaction, I canceled the subscription myself, but the charge had already gone through. I don't accept such a high amount being charged this way without any notification.
I want a refund for this payment, which was charged without warning after the free trial ended. I am requesting that the amount be returned to my card/account as soon as possible.