I have contacted Sectigo and they said they can’t revoke a certificate if issued by CF.
The certificate is found by the website you provided. However, when I enter the domain it needs to send a code to specific email address associated with the domain. I don’t receive the code, but receive other emails at that specific email address.
Did you test the email address from an external provider, that does not have anything to do with your current email system?
And that could be an issue with Sectigo and their email system, which is why you need to troubleshoot with them, regarding why they are not sending the messages (or what errors code(s)/message(s) they see, while trying).