bally123 - you might want to let go of the whole contact form idea. Seriously, post an email address encrypted or as an image and let people click on it.
Here's my opinion of contact forms that make me enter a lot of data to ask a question - either I don't bother, or, I fill it in with bogus data - unless I REALLY want to communicate with the people. If the contact is initiated through email, a response through email is fine. If, after a response, further discussion is warranted, then phone numbers and addresses can be exchanged.
This is really a business decision. All you need is the email address of the person who contacts you. You have to decide how much time (which is also money) you want to spend getting that email address or letting people send you messages, and how much time and energy you want to waste on the idiots that are abusing your form.
Don't feel bad - this is a big problem, for a lot of people, and there are many valid solutions. Jcbones has a nice one, and all the code is there. (Thanks Jcbones!)
Finally, you can always change your site later, so the decision isn't permanent.
Good luck.