Someone is using my email address to send spam and my mail box is full with the mail not delivered. How can I?

When I clear my mail box it keeps fulling up the same thing, Mail Delivery Subsystem or return mail or mail demon, how can I stop it?

Someone is using my email address to send spam and my mail box is full with the mail not delivered. How can I?
Change your password and dump the sent folder. Keep dumping them. You can try vacation response to shut your address down for a while if you want. Call Y security:866.722.3425. Don't block your own address or you delete your account.