The same thing happened to me today. It is sheer idiocy to send an email saying that your mailbox has been locked!
There certainly had been "suspicious activity" on my account: I had been receiving a deluge of spam, most of it claiming to be from Virgin Media!
My email account had not been sending any spam, because I do not have an email client - I use webmail. (That was hacked last year, but that's another story...)
The "Internet Security" team are anything but.
I have found that I can't change my password - apparently because it won't accept my date of birth: this seems to be because Virgin Media don't know my date of birth!
