I did, but not with contact form 7. I installed Fast Secure Contact Form and they have a regex option for each field. So what you do is under the “Promo Code” field (or whatever field you’re needing it for), enter ^yourcode^. This will then require the field to match your code. Make sense? You can also add a return error message if they don’t enter the code correctly. It’s a great tool. Let me know if you have any quesions!
