I have discovered a CRITICAL Security Issue with your <ISP_NAME> WebMail platform that allows ANYONE access to ANYONE’s mail box WITHOUT knowing their password. Clearly this issue needs to be fixed IMMEDIATELY as it not only puts my mailbox at risk but also the mail boxes of every one of your customers along with any personal details they have sat in their e-mail.
As this is such a sensitive issue I will not describe the method I used to do this by e-mail but instead I require that a SENIOR Support/Development engineer call me immediately on this number: <My_Mobile_Number>.
To prove the issue exists I have attached to this e-mail a screenshot of the support@<ISP_NAME> mailbox and it’s contents.
Clearly this is an embarrassing issue for <ISP_NAME> and it would not be great for your reputation if I were to release this information into the public domain, however if I do not hear from you within 24 hours I will have no choice but circulate the existence of this serious flaw in order that customers can protect themselves.