If your payment was not processed properly due to technical issues and no Coins were added to your account 24-48 hours after your purchase attempt, you will not actually be charged because your payment was not processed completely.
Restarting the WEBTOON App after a few minutes after the purchase would help verify if the Coins purchased will reflect on your "Coin Shop" page.
If the payment has not been cancelled or refunded within 24-48 hours, please reach out to our Community Support team to confirm if your purchase was successful or not. Our Community Support team will let you know if you should further contact your original point of purchase (Google Play Store or Apple App Store) and file a refund request if needed.