Ok, sure thats not a problem.
1. When you create an addon domain it always creates a subdomain as well, its just the cPanel way...
2. How are you trying to login to webmail?
you@yourdomain.com or?
3. The default email address is known as the "catchall" email address that we do not support in our network due to issues with being attacked by spam bots in the past, so this feature is disabled.
4. what is your domain name so I can check the NS servers and the MX records.
Does the site work, just the email or?