Hi @Harvey1. Thanks for being part of GoDaddy Community! Your email addresses on your cPanel plan won't work unless your domain's DNS points to your cPanel email service. Take a look at the information in this post. If you make sure your DNS records reflect what is mentioned there, the addresses hosted on cPanel should work. Keep in mind that you won't be able to use both email services simultaneously.
As for accessing the addresses, if your DNS is set up correctly, you can usually get to them by visiting domain.com/webmail. It will redirect to a cPanel webmail login page.
JesseW - GoDaddy | Community Manager | 24/7 support available at x.co/247support | Remember to choose a solution and give kudos.