flo on "spam via contact form"

hi

Spam messages via my site have increased recently, where at least one spammer seems to enter messages via my site's contact form, despite enabled Captcha.
Spam seems to be sent twice a day entered via contact form at least the messages that i then receive look identical to any message entered via my site, i.e show as sender the email as registed with my site. The message body contains blabla and many links.

somehow i have trouble believing a spammer enters regular spam twice a day manually, hence i wonder is there a way to circumnavigate the Captcha somehow?

any advice as to how such spam can be avoided or reduced?

thanks
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