In-game purchase via Google Play not going through? Here are the common causes.
Cause 1: Insufficient Balance
Most common. The pack costs more than your current balance.
Fix: Top up Google Play Balance at marix.app.
Cause 2: Game Installed via APK
Google Play payment doesn't work for sideloaded games.
Fix: Reinstall the game from the Google Play Store.
Cause 3: Wrong Account Linked
The game is linked to a different Google account than your Play balance.
Fix: Link the correct Google account in the game settings.
Cause 4: Daily Transaction Limit
Fix: Wait 24 hours and retry.
Cause 5: Regional Conflict
Game server region doesn't match Google Play account region.
Fix: Align your Google Play region with the game's server region.
Summary
Top up your balance at marix.app, ensure the game is from Play Store, and verify the correct Google account is linked.