I've forwarded the letter to mail.com and asked them to disable the account.
I did that a few days ago. They used to be very good at closing down accounts but I've had no feedback and the account still appears to be live, as emails to it don't bounce. Behind the scenes, I've done quite a bit more which I won't publish here (PM me if you want to know) , but let's just say that these people will be having some problems with continuing to try to scam people with this particular scam. Of course they will just set up again and carry on but it does make life awkward for them and if it only saves one person then it's served a purpose.