Well, this may happen due to a poor or the lack of connection. So make sure your WiFi or mobile data connection is active and working whenever you want to purchase something with your game currencies.
Let me explain you more throughly. When you purchase something, this is registered in your game client, which is basically the things that you do only in your device. To make sure this transaction happened accurately, we send this information to our server right away. This one validates the transaction and send you the item purchased.
This communication happens very quickly, so it's almost unperceptive. But the thing is: if the client fails to inform the server, or if the server fails to send you the item due to poor internet connection the game corrects it automatically on the next log. So your currencies get back to you. :)
So here you have a troubleshooting: If you bought something and it wasn't immediately delivered to you and the diamonds were deducted, try assuring that your internet connection is full working and reopen Zooba. Then, check if the currencies are back.
If the item you have purchase was not delivered and the currencies were not restored, don't worry! We're here to help, so tap here to check how contact us!
Don't forget to tell us what was the date and time of the purchase, what you've tried to purchase and also how much was deducted so we can check our logs! :)