New user or customer profile keep diseappering

Hello there,

I have a problem. Since January this year, I have 1000 users ( customers ) in my wordpress site, it was gone and left about 30 users.
I hired a tech guy to clean up my site for any malware.

Now I create users manually in my wordpress dashboard, after a weekend the users are gone, they simply disappear.
The woocommerce orders can not show up the customer’s name, instead it shows up “guest”.

What could be the reason, that my users / customers keep disappear?

Regards,
Yuki

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