You will have to pay for it and then request a refund. That's how Apple does things with reconsidered pending purchases.
Read the links below about various ways to pay for items in the iTunes and App Stores.
- Add a payment method to your account. See this article about payment methods that you can use with your Apple Account --> Payment methods that you can use with your Apple Account - Apple Support then see this article about how to add a payment method to your Apple Account --> Add a payment method to your Apple Account - Apple Support
- Add money to your Apple Account balance - "Use a payment method, such as a credit or debit card, to add funds to your Apple Account balance." This takes the previous payment method one step farther by optionally using it to irreversibly add funds to an Apple ID account balance instead of having the card charged each time.
Click here --> Add money to your Apple Account balance - Apple Support
If no option is shown to "Add Money to Account" using this method (you only see using gift cards) then it may not be available in your country. Use a gift card instead.
- This article outlines how to redeem an Apple Gift Card or App Store & iTunes gift card --> Redeem your Apple Gift Card, App Store Card, or App Store & iTunes Gift Card - Apple Support
- You could also look into joining a Family Sharing group where the family Organizer's payment method is used. To learn how to join a Family Sharing group, read the section "Join a family group" in this support article --> How to set up Family Sharing on your iPhone, iPad, or Mac - Apple Support
Here's how to request an app or media refund from Apple (From: Request a refund for apps or content that you bought from Apple - Apple Support - see the article for more detail.) If you bought this from a third party, see: About purchases not billed through the App Store or Apple In-App Purchase - Apple Support instead.
1. Sign in to https://reportaproblem.apple.com
2. Tap or click "I'd like to," then choose "Request a refund."
3. Choose the reason why you want a refund, then choose Next.
4. Choose the app, subscription, or other item, then choose Submit.
If you were charged for a subscription that you no longer want, you can also cancel the subscription using the directions in this article --> Cancel a subscription from Apple - Apple Support
Read this support article for information about how long it takes to receive a refund (if you are granted one), and how to check the status of a refund for apps or content that you bought from Apple --> Check the status of a refund for apps or content that you bought from Apple - Apple Support