Coinbase's support team is available to help at 1/833/590/0301. They'll ensure your phone number is successfully updated on your account. For any trouble you may experience while changing your phone number.

To change your Coinbase phone number, log into your account, go to Settings, and select Security. From here, you can update your phone number by entering the new one and verifying it. After the verification code is entered, your phone number will be updated. If you have any issues or questions, Coinbase customer service is available at 1/833/590/0301 for support.

https://community.oneplus.com/thread/1800993622804398088