Reporting Phishing E-mail

I try to report all phishing e-mails to Cox and the organization the e-mail is spoofing, e.g., Navy Federal Credit Union (of which I am NOT even a member).  I send Cox to phishingreport@cox.net and for the spoofed organization I use the address shown on their web page, e.g., phishalert@navyfederal.org.

I always try to send the offending e-mail as an attachment and paste the headers in the body of my original e-mail, identified as such.  My outgoing e-mail to Cox, et. al. is normally about 14 kb, but I get a response similar to the following nonsense response from Cox through an error message on my mail program (Windows Live Mail, using Windows 8.1):

"This message could not be sent because its size exceeded the server's limit. You can use the option, located in Tools | Accounts | Properties | Advanced, to break messages into smaller parts.

 Subject 'Phishing Email received Fw: Your Have Two New Security Message From Navy Federal'

Server Error: 552

Server Response: 552 5.2.0 kLkW1q0030sfaii01LkW24 This message was undeliverable. This message has been found to be a potential spam message, and has therefore been blocked. Please visit http://ww2.cox.com/coxagainstspam for more information.

Server: 'smtp.east.cox.net'

Windows Live Mail Error ID: 0x800CCC6D

Protocol: SMTP

Port: 25

Secure(SSL): No"

How can I report phishing e-mail if you block it from being sent to the applicable security folks.?  The message is NOT too large!  Please provide me guidance.

Thanks.