Contact us form being hijacked

Somebody, somehow is injecting code into the contact us form on my site canemasters.com and they are sending spam to other people than the form is suppose to send to, and my host is about to shut us down for it. I'd like to put a secure php form mailer called dd-formmailer located here: http://www.dagondesign.com/articles/secure-php-form-mailer-script/

How would I go about turning off the current contact us script, and installing this one. I'm sure it's a sinch, but I'm no coder so I havent the slightest clue. The instructions on that site aren't too user friendly either. They say it's easy, but I cant figure it out. :wacko: :unsure:

Thank you.

If the contact form is hijacked, doesnt that mean your site has some security problem? The contact form simply takes the msg, then send directly to you using the store email from database.

What version of Zen Cart are you using?

In addition to what version of Zen Cart, what addons/contributions do you have installed?
And, which SEO module are you using?

How is your host so sure that someone's hijacking your contact-us page?
Do they have proof that the spam you're being charged with came from your webpage? Is it possible that someone is sending emails from their own computer but impersonating you by using your email address as the sender name, etc?

I have every contribution under the sun installed, that's why I'm still using 1.37. Let me rephrase what's wrong. The contact for is not hijacked, somebody is cleverly injecting code into either the subject or body of the message and is using it to spam other people, and it looks like it's coming from us.

I'd really like to incorperate this dd-formmailer into my site.

Is it possible?

Unless you are talking about the refer a friend form, I cant see how someone can do that with the Zen Cart contact form.