Limitations - Submissions

I have a contact us form. Is there a way to limit the amount of characters someone sends? I've been receiving far too much spam. I believe this would assist in responding to valid leads properly and efficiently. Someone sent me a massive amount of text with links. I'd like some limitation if at all possible.

www.privin.net/contact-us/

We have a limit entry in the long-text entry field, please check my screenshot below for reference.
You can also enable unique submission if you receive spam submissions from the same person multiple times.

Guide: https://www.jotform.com/help/64-how-to-set-unique-submissions-on-a-form