Given what you said in your first two posts, Apple should have charged you immediately for the app if you actually had to buy the app. A delay of a few days means the app has a free trial which has ended and turned into a paid subscription. So what you say about there being no subscription but the charge being delayed for a few days doesn't really make sense in terms of how Apple operates.
If Apple wants to charge you, you have to pay. You can then try to ask for a refund, but those are not guaranteed. 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 in the EU from a third party, see: About purchases not billed through the App Store or the App Store’s In-App Purchase system - 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 --> If you want to 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
