How to add an exception for email in Hotmail?

I have a website with a contact form. Often when people send me email from the website the message ends up in Junk folder. Email subject is always the same. I was wondering if I can add that subject to the exception list so that it is not considered spam.

I already tried selecting "Not Junk" many times, it doesn't help.

(I'm using the new version of Hotmail (Outlook layout) if that helps)