Relay access denied, Outlook sending of mails

Been on call to Telkom for a very long 7 weeks now. Not able to send e-mails from outlook as of when Telkom had issues with internet down. Numerous calls and yet non the wiser. Not able to send any mails from outlook, receiving mail is fine. Can't even send to my gmail account. Really pathetic. Error I get, "Server error: '554 5.7.1 <??????????gmail.com>: Relay access denied', on all mails send. What to do next?