how can CHARTER or will CHARTER unblock my e-mail from the ERROR 550 ???

CHARTER itself put a 550 block on an e-mail from a very good friend about an American HERO and now I can only receive e-mails but cannot send them. This is the first and only BLOCKED e-mail I have ever had or seen. Can YOU mend it by unblocking my 550 error - seems that CHARTER can't or won't. Can you help me get my e-mail back??