Purchases are usually delivered instantly, but may in some cases take longer.
When such delays occur, it means the purchase is still being processed. There is no need to try purchasing the same pack again - it should arrive soon.
In the meantime please try the following troubleshooting steps:
Reboot your mobile device
Make sure the Internet connection is working correctly. If possible try another Internet connection – for instance from WiFi to mobile data
If you still haven’t received a purchase after 24 hours, please contact Apple support. All payments made toward the game are processed by Apple. You can reach them here: https://support.apple.com/contact
Accidental purchases can be avoided by setting restrictions in your device. Check out the article "How do I restrict in-app purchases on my Apple device?" or this link from Apple: https://support.apple.com/HT204396