Icloud in danger

Hello today i had recive this email

I have a person who is trying to blackmail me with different information and i am affraid that he might hack my account.

When i logged in in to my icloud i seen that it was another Iphone4 who was using my Icloud. Can you please tell me what other devices were using my icloud and also the location -from where they have been using it?

[Image Edited by Moderator to Remove Personal Information]