can't receive emails- telnet

[steve]

Our emails are not being received. It was suggested by
ATTGlobal that we "telnet" to find the problem and delete
an email that might tie up our system and not allow others
to come in ("stuck email").

Doing the telnet program in DOS I can get a message
saying "+ok" which I understand I should get but after
that message, I can not type anything else to continue the
telnet. The cursor blinks but no typing can be done.

Any ideas?