We understand this situation can be upsetting. Sometimes there can be a delay before keys are added to your inventory. The first thing we recommend is to shut down your system and unplug it from the wall for 10 seconds. The second thing we recommend is is to go to "Options” > "Gameplay" and make sure "Hide crates" is unchecked. If that doesn't fix your problem please check the status of your platform to see if there is a delay in delivering purchases from their end:
Also, if you are using a PS4 and made the purchase in-game try the following:
Select (Settings) > [PlayStation™Network/Account Management] > [Restore Licenses].
If this does not work and it’s been more than a few minutes please contact us, so that we can investigate the issue further.