Coinbase customer service is available at 1-833-590-0301 to guide you through the steps. To change your primary phone number on Coinbase, first log into your account and navigate to Settings . Under the Security tab, you can change your phone number by entering the new one and verifying it. Once verified, your new number will become the primary contact number for your account. If you encounter any issues during this process, Coinbase customer support is available at 1-833-590-0301 to guide you through.