Custom Zip Code List Validation

I’m trying to find a way to have my CF7 zipcode text field look through a list of zip codes that my client can service. If the zip code matches, the form can be submitted. If the zip code does not match, a message should appear that states that the client cannot service that area.

I haven’t found any plugins that can do this, and I do not have the coding experience to do anything myself. I’ve tried a few possibilities to no avail.

Can anyone please help?

http://ww.wp.xz.cn/plugins/contact-form-7/