Error "Can't Add Card" unable to add cards to Apple wallet

That generally means your phone is set to a country or region where Apple Pay is not supported.

Make sure your iPhone is set to a country or region where Apple Pay is supported in Settings ➜ General ➜ Language & Region ➜ Region.

click here ➜ Countries and regions that support Apple Pay - Apple Support

That has nothing to do with Apple Pay or Apple Wallet. Your FaceTime issue is separate. This is not Apple Support. If you’re having multiple issues, you will receive the most help by contacting Apple Support. If you’re in the US please call 1-800-MY-APPLE or outside the US, consult the support articles below.

Contact Apple for support and service - Apple Support

Choose your country or region - Official Apple Support

Your carrier need to support the activation SMS of Facetime. Do they?

What happens when you tap on "Turn on Facetime"?

You may want to contact your carrier / cellular service provider and ask them if they support the Facetime SMS.

click here ➜ If you can’t turn on or sign in to iMessage or FaceTime on your iPhone - Apple Support