First try the following in-game.
1. On the main screen, tap Menu in the bottom right.
2. Tap Gold Pass in the banner at the top of the screen.
3. Scroll to the bottom.
4. Tap Complete Purchase.
If that does not fix the problem, please see the below.
In order to use the Gold Pass, you need to be signed in to the App Store with the e-mail address (Apple Account) you used when you purchased it. Please check to see if the e-mail address you are signed in to the App Store with matches the one that shows up in the receipt e-mail that was sent to you when you made the purchase, then if it does not, please make it so the e-mail you are signed in with on the App Store matches the one you were signed in on when you made the purchase.
If your issue is not resolved even after checking the above, please contact us using the Support form at the bottom of this page.
Note: Our investigation will go smoothly if you provide us the following information when you contact us.
・ The fact that the Gold Pass has not been reflected
・ The fact that you tried the steps in the FAQ, but it did not resolve your problem
・ The support code and/or error message that was displayed