Sophisticated spam attacks pass the plug-in?

Hello, we are using CleanTalk Anti-Spam plug-in and were always happy with it, till we began to get messages (definitely sent using our online form) with the following content:

“How do.I unsubscribe from getting these emails.”

“Please stop sending me your dating pages.”

and so on, with a little difference, but the subject was always “you spam me”. At the beginning, we thought it were real people who got spam emails that appeared to be from us. We replied several of these emails, asking to re-send us the original email, but nobody of these “people” replied (we looked in the spam folder, too).

We assume it is a kind of a spam attack that managed to pass the plug-in. We have additionally installed a captcha on our form, and the amount of such messages has reduced. But today, we get a new one. We are about to blacklist all the senders of such messages. I wonder why there are no such messages were reported by the network users. Maybe the content of these messages is confusing to blacklist the sender? Truly, each time we get such a message, we must think there are real people behind it ??

Regards,

Natalia

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