My email address is being used as return address in spamming??!! Help.

I don't know where to start. Please help me with answer or direct me to where I can be helped.

I am getting about 20-30 of the following every day. I am told that someone is using my email address as a return address in doing spamming. (My domain is registered with 1and1 and hosted with Lunarpages).

I would like this to stop. How can I get this to stop, short of cancelling that email address? Thanks.

The message I'm getting is:

From: "Mail Delivery System" <>

To: <proxy465014@1and1-private


Sent: Sunday, March 25, 2007 10:36 AM

Subject: Mail delivery failed: returning message to sender

> This message was created automatically by mail delivery software.


> A message that you sent could not be delivered to one or more of

> its recipients. The following addresses failed:


>  <>


> SMTP error from remote server after transfer of mail text:

> host[209.200.2


> 550 Administrative prohibition



> --- The header of the original message is following. ---


> Received-SPF: none (mxus0: is neither permitted nor


> by domain of 1and1-private-registration

.com) client-ip=;

> envelope-from=proxy465014@




> helo=201-208-5-105.generic



> Received: from []




> by (node=mxus0) with ESMTP (Nemesis),

> id 0MKpe3-1HVXZw1qFx-0003om for

> proxy465014@1and1-private-

registrati; Sun, 25 Mar 2007

> 14:36:32 -0400

> To: proxy465014@1and1-private-


> Message-ID: <0MKpe3-1HVXZw1qFx-0003om@



> Date: Sun, 25 Mar 2007 14:36:32 -0400

> X-Spam-Flag: YES