Someone is using my domain to spam

[incka]

Someone is using a strange random letter code @incka.com (my domain) to spam.

incka.com has 0 POP3 boxes so they are masking there email address though it.

I could be sued for their actions in my country.

How can I stop them?

[Westech]

You'll need to get ahold of one of the spam emails so that you can examine the header to see where it really came from and report this to the spammer's ISP.

You might also want to contact your host or datacenter and explain the situation. This can help you in two ways:

1.) They may not just automatically shut you down when they start getting complaints.
2.) You may be able to convince them to start logging your site's traffic so that they can later certify that there was no outgoing email traffic from your site during the the time that the spam emails were being sent.

This can be a messy situation to get out of. Good luck.