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 haven’t received your order after more than 24 hours, please contact Google Play directly here: https://support.google.com/googleplay/answer/2479637 and scroll down to 'Request a refund on the Google Play website'.
Accidental purchases can be avoided by setting your device with restrictions. See the article "How do I restrict in-app purchases on my Android device?", or check out this link from Google: https://support.google.com/googleplay/answer/1626831