As Rassle said, take a screenshot before you log out and after you login, upload the images to an image hosting site, then contact support including the links to the images, if you use live chat you can get an instant reply, but as this seems a definate bug (I have never seen account hackers act in this manner, they normally gut the account and change the password) they will probably have to investigate beofore they can do anything (the investigation will also include IP addresses accessing the account to see if the account has been compromised as well).