validation.com was the site (still anonymously registered domain) they were sending me to, and they confirmed from a support ticket that the email request was sent by them, you can see on the site an example of the credit card cam show they require.

The support ticket took 5 days and they shut down my account later that day, actually while i was trying to get a buggy old webcam to work.

They actually mention validation.com now; https://www.namecheap.com/id-validation/ though i couldn't find any reference to it at the time.