I want to buy more point in Call of Duty Why won’t let me

Check ⤵️

1.

Manage App Store purchases, subscriptions, settings, and restrictions on iPhone

Manage App Store purchases, subscriptions, settings, and restrictions on iPhone – Apple Support (UK)

2. 

If you get a message -> Your purchase could not be completed, you need to update your payment method or add a new one. 

See the following Apple articles:

Payment methods you can use with your Apple ID

Payment methods you can use with your Apple ID – Apple Support (UK)

Add money to your Apple ID balance

Add money to your Apple Account balance – Apple Support (UK)

Click here for more support and assistance.