Maybe don't trust it?

It seems to accept sharklasers.com (aka anonymous) email addresses though, so you don't have to use your real email address. :)

It also seems to work via Tor Browser, although it's a bit slow.

Technically you are buying VPN services by giving your credit card :D

use a dummy email -- if you feel so unsafe. At least Squarex is free right now so no credit card needed

You can pay for VPNs with crytocurrency instead

For Mullvad you can buy gift cards as well. Even if you pay for those with a credit card, there's no link between the payment and the contents of the gift card.

I send cash and it has worked just fine. I guess depends on honest mail people between you and them though.