Spoofed Emails/Authentication Error

[#1]

Signed up to Plus Net yesterday, received 4 emails from them. All emails have been tagged by my email provider with the below message:

"This email has failed its domain's authentication requirements. It may be spoofed or improperly forwarded"

Any one else getting this?

I tried contacting customer service who tell me to delete cookies (for no apparent explanation as to how that could possibly help) and they refuse to put me in touch with anyone with technical knowhow. I am seriously considering canceling my order.

Any input would be appreciated.

Moderator's note by Mike (Mav): Post released from Spam Filter.

[#2]

Thanks for getting in touch with us via our community forums.

I've raised this internally to look into. Thanks for flagging.

[#3]

What's the sender address of these emails? Can you post a copy of the email headers with your email address redacted?