Tap Continue and sign in to view your billing information.
To verify / view your payment information uou need to -> Sign in to your Apple ID account page and edit / update your Apple ID details -> https://appleid.apple.com
On the Sidebar click Payment methods -> then tap Payments Methods and tap Manage payment method.
Or -> Add a payment method to your Apple ID
Add a payment method to your Apple ID – Apple Support (UK)
- If you want to change your card, add first the new card, then remove the old one.
- or if you use your Apple ID balance, set your Apple ID balance as your default payment.
See also -> Payment methods you can use with your Apple ID
Payment methods you can use with your Apple ID – Apple Support (UK)
You can also use your Apple ID balance as payment method: Add money to your Apple ID balance
Add money to your Apple ID balance – Apple Support (UK)
If you update your payment method or add funds to your Apple ID balance, It would take about 1 to 3 business days in order to process.
If you're still unable to update your payment method, Contact Apple Support.
Additional:
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Try to optimize the range of the mobile network, see this Apple article:
If you see No Service, Searching, or SOS on your iPhone or iPad
If you see No Service, Searching, or SOS on your iPhone or iPad - Apple Support
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Low Power Mode is On.
Charge the iPhone & wait until the battery is fully charged (100%).
The Low Power Mode will turned off automatically.