Worth a recaptcha. There are fakes on the site. Where to look for a problem?

Question

reCAPTCHA

There is an online store site. It has 2 types of buyers: retail and wholesale. Each type of buyer has its own registration form. Registration forms are made using the pie register (for retail) and wp_registration (for wholesale) plugins. Every day, about 100 fake users register on the site (the type of users is retail). It's most likely a robot that's chasing them. The form uses reCaptcha, but fakes are still registered. All pages and records of the site were viewed. Forms are not duplicated anywhere and are no longer displayed. By the way, the site was on 3 different domain names and fakes were registered everywhere.
How are fakes registered? Can there be a code in the plugin itself to buy the paid version? Maybe someone had a similar situation.

Answer 1

well 100 users is not so much. Would you look at the logs of these registrations - maybe it's the same person manually registering? Decided to tell you someone can?

Answer 2

Recaptcha breaks without problems by the corresponding services.

Answer 3

Here is an interesting captcha that works in POST mode: after clicking on the button on the form.