If your mail reader configuration is OK, and you can receive mail but not send mail or access the control panel, your account was probably temporarily disabled for sending mail beyond the limits set for your account (see Account Limits). In the disabled mode, your mail will still be received, and you can still pick up your mail, but you can not send mail or log in to the "My Neo" area of the site.
Just contact support if you can receive mail but cannot send mail or access the "My Neo" section of the site, and we'll re-activate your account and increase your limits if necessary.
Generally, as long as you're sending legitimate mail and not spam or unsolicited commercial mail, we'll be happy to raise your sending recipient limits to whatever works for you. Contact support to get your limits raised.
If you expect to be sending mail in larger quantities than the default limits for new accounts allow, it's a good idea to let us know beforehand and have your limits raised. That will prevent your account from being disabled if you go over the default limit.