I bought but didn't get the coins
I bought coins in a slash game
I didn't get it even though it was debited from my bank account
iPhone X, iOS 15
See -> Request a refund for apps or content that you bought from Apple.
Request a refund for apps or content you've bought from Apple – Apple Support (UK)
If you have requested a refund, you must wait until Apple has approved. Then you will receive a message from Apple.
Refunds are not guaranteed. For more information, see the Terms & Conditions.
Then see -> 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've bought from Apple – Apple Support (UK)