Large Number of Fake Accounts

[thegoodlifestore]

We have a website that is receiving an INSANE amount of fake accounts being set up daily. There is a reCAPTCHA code on the registration page, but that hasn't slowed them down at all. I installed the Delete Spam Account add-on from The Software Guy and that helps with cleaning the bad accounts out easily, but it's now a task I have to do multiple times a day. Is there any good solution for blocking these kinds of sign-ups?

https://www.platinumpapersstore.com/...create_account

The site is running:
Zen Cart 1.5.7c
PHP 7.2

The only add-ons running on the site are the Delete Spam Customers and reCAPTCHA ones.