Hi Stumbler! Fireman Torch here to assist you with any concern you may have 🚒
We are sorry to hear about this, however items/gems/tokens do not disappear from accounts randomly. 

This means that someone has access to your device/account and has used the gems/tokens.

You have requested a refund successfully and your account has been rolled back to the state that it was when the purchase was made.
Glad to be able to assist you!