Thread: Is there a way to block specific emails from submiting via ads contact form?

Is there a way to block specific emails from submiting via ads contact form?

Is there a way to block specific emails addresses from submitting via ads contact form?
I identified that car sellers that are not logged in the site are sending spam emails via ads contact form. E.g. Ads related to cars. Some car sellers are sending spam messages to all users of the site that put their cars on sale asking for hiring them as their sellers.