As the issue is not clear, I tried to find the Site24x7 account related to this email and found an evaluation account which was created on Dec 22 at 9:38:36 PM PST.
I checked all the account configuration and did not see any issue with it. It will be helpful if you can provide some additional info on the actual issue.
Like, did you had any account in Site24x7 with this email and not able to see the monitors now. If so, you can provide any monitor name or url that was monitored in the account.
You can also reach to Site24x7 support at support[at]site24x7[dot]com and we assure you a quick resolution to the issue. You can attach this forum post link too in the email.