What I don't get is this; I get HUNDREDS (half a thousand FYI) a day in Feedback... And ZERO comment spam. What gives and why is the Contact Form so vulnerable to spam?
That mostly depends on the spammers who found your site. One single spammer might have found your contact page and keeps submitting forms.
It might be worth trying to change things a bit to try to make things a bit more difficult for that spammer. Try adding an additional required field, maybe?