a fraudulent denaust

I know this is hard to believe. I would myself like to know how it happened. My name "denaust" has been used by someone who you may know who somehow got hold of my password. I'll paste what I sent to hotcopper. They incidently find it hard to believe themselves.. But it is true.

"Dear Hotcopper,
Someone has been using my account to obviously flame and downramp. When
"denaust" and I logged on was suspended I realised someone else was using
it.
My password was "buzz" Which I changed last night. This old password was
obviously cracked by I do not know who. I have not posted in many years
but enjoy reading posts. I'm lucky the suspension did not include
cancelling of my membership!
If you are able to trace these posts I would be very happy. It is
extremely dishonest and this person should have his membership cancelled
and prosecuted if possible. I am happy to furnish any further evidence.
The posting suspension until 6 December does not concern me because at
present I am a post reader.
Yours Faithfully"
(Name Removed my me)
Any information would be helpfull
THANKS