Am i sending SPAM

[c0mputerking]

I have some of the following in my top senders by quantity none of these address exist on my server, how can they be sending email?

blair@decisivefarming.com 17,478 791.1Mb
srs0+680b8ce3fdd183d8=6z=mulhak.com=news@smsandco.com 14,407 767.1Mb
info@granfondodellapace.it 14,285 23Mb
redwingshoes.ca@computerking.ca 9,278 14.6Mb
notification+pk7k1dvd@facebookmail.com 9,038 189.4Mb
update+pk7k1dvd@facebookmail.com 9,031 131.6Mb
bounce-mc.us5_16716331.399461-lynatparkland=yahoo.ca@mail140.atl121.mcsv.net 8,893 436.6Mb
alonzo.j@pleasurableout.com

I also have this in my top relays report how do i stop these from using my system as a relay??

sulafat.bluefalls.ca 72.13.188.132 Canada 26,141 0 1 981.2Mb
(Hostname lookup failed) 10.0.0.104 (GeoIP lookup failed) 24,968 0 5 39.4Mb
pcc-yyc-mx-02.platinum.ca 69.31.192.19 Canada 17,799 0 105 320.7Mb
mail183.atl121.mcsv.net 198.2.131.183 United States 17,025 0 0 902.5Mb
smtp.smsandco.com 94.236.102.104 United Kingdom 15,208 0 815 801.1Mb
server1.trinatel.it 5.134.125.51 Italy 14,285 0 8 23Mb
mail22.atl51.rsgsv.net 205.201.135.22 United States 11,350 0 0 602.7Mb
nm8-vm0.bullet.mail.bf1.yahoo.com 98.139.213.95 United States 8,899 0 2 436.9Mb
199-193-115-67.static.hvvc.us 199.193.115.67 United States 8,864 0 1 62.5Mb

[shawniverson]

Top Senders are senders that are sending email to your domain.

Top Relays are relays from which your system is receiving mail.