Guess I'm SOL then. Just one of the many perks of owning your own domain name.
Edit: wow, I just checked my spam folder, and found 7 more...
What the others say is the sad truth..
about ten years ago I suffered the exact same thing on both
of my domains..
At times I was getting over 600 returned emails a day..!!
I was able to trace my culprit to Nigeria..
Everything I did failed..
After seven weeks I figured I'd risk trouble and
regain my sites or disband them..
A virus the offender received solved my frustrations..
I have now embed a small " present/gift
" within everything
upon my domains so were a pic, gif, sentence, word, etc.
copied FROM said domains and then pasted,
the thief would be rather upset...
This DOES not stop automated scans and crawlers
( or humans ) that just choose domain names at random..
In that case I still have found no way to stop this issue as
most POP type accounts and their security work more
or less on an " honor code ' type of system..
I normally would have refrained from posting
since my coding seems to offend " some " here.....
But I wanted to at least give you some encouragement
that you are not alone, and problem IS a common one..
But what has happened to you will usually not last more
then a few months until " whomever ' moves on to the
next account/domain name....
Because they are NOT actually utilizing YOU account/servers/smpt
but in affect just using your name " pasted over " their real stuff.
So changing your account is null and in vain.
And the risk of having your domain (s) blacklisted is very real..
( one of mine WAS )
Wish I had a solution, but afraid I do not..
Be advised the creeps ALSO utilize private email too..
They will grab a valid ID like abc123 @ say example Yahoo/Google etc..
and use that too..
The problem IS frustrating, and ALL the governments are fully aware
of this issue....
My advice is stay strong, don't do anything crazy, and CONTINUALLY
monitor your email as you might find something in their to lead you
to the perpetrator..
If there is anything "good" about this...
Knowing you were NOT personally targeted,
but simply a random victim is about your only consolation ..
I wish you luck my friend..