For security purposes, Coinbase does not support the delivery of 2-step verification codes via voice call. If you have a landline registered with your Coinbase account, follow these steps to upgrade your security:
- Sign in to the Coinbase website with your username and password.
- Click I need help > I need to update my phone number
- Complete the Account Recovery process by following the steps listed
- Increase your security by enabling Authenticator: https://www.coinbase.com/security_upgrade