Apple Cash funds declined for in-game purchase

Your in-game purchase may be declined because Apple requires a secondary backup payment method (like a debit or credit card) on file, even when using Apple Cash. 

Try this

• Add a Backup Card: Open the Settings app on your iPhone, tap your name, then select Payment & Shipping to add a standard credit or debit card. 
• Refresh Payment Details: Remove your current payment method and re-add it in your account settings to clear temporary glitches. 
• Check Your Balance: Confirm your Apple Cash balance fully covers the total cost, including any local taxes that might make the final price higher than expected. 
• Verify Account Status: Look for any red warning text under your payment methods in your account settings indicating an unpaid balance or verification issue.