Most of these issues are caused by players accidentally spending Balens in the Blacksmith or the Stable.
Gem Synthesis and Mount Training
Remember that you will not be charged Balens, if you have enough Gems or Mount Training Whips.
If you do not have enough Gems or Whips, you will be charged the difference in Balens in order to complete the Synthesis or Mount Training.
How to prevent this
Please be extra careful when navigating these menus by not tapping too quickly on the Confirmation Buttons.
Tap each button one time and wait a moment before you try again, making sure the tap was recognized.