Spammers ignore 550 command

Having written about the effectiveness for blocking, we have a spammer that is still trying to send emails to the same email address, on a different server and after a failed previous attempt where a 550 no suvh user was given;

Sat 2011-12-17 05:43:06: [468:256] Accepting SMTP connection from [67.159.33.100]
Sat 2011-12-17 05:43:06: [468:256] Looking up PTR record for 67.159.33.100 (100.33.159.67.IN-ADDR.ARPA)
Sat 2011-12-17 05:43:21: [468:256] The name server reports that it is having technical problems.
Sat 2011-12-17 05:43:21: [468:256] --> 220 xxx1.xxx.xxx ESMTP MDaemon 6.7.9; Sat, 17 Dec 2011 04:43:21 -0500
Sat 2011-12-17 05:43:21: [468:256] <-- EHLO super.jbcapacitacionempresarial.com
Sat 2011-12-17 05:43:21: [468:256] Performing reverse lookup on super.jbcapacitacionempresarial.com (looking for 67.159.33.100)
Sat 2011-12-17 05:43:22: [468:256] D=super.jbcapacitacionempresarial.com TTL=(240) A=[67.159.33.100]
Sat 2011-12-17 05:43:22: [468:256] --> 250-xxx1.xxx.xxx Hello super.jbcapacitacionempresarial.com, pleased to meet you
Sat 2011-12-17 05:43:22: [468:256] --> 250-ETRN
Sat 2011-12-17 05:43:22: [468:256] --> 250-AUTH=LOGIN
Sat 2011-12-17 05:43:22: [468:256] --> 250-AUTH LOGIN CRAM-MD5
Sat 2011-12-17 05:43:22: [468:256] --> 250-8BITMIME
Sat 2011-12-17 05:43:22: [468:256] --> 250 SIZE 0
Sat 2011-12-17 05:43:22: [468:256] <-- MAIL FROM: SIZE=48915
Sat 2011-12-17 05:43:22: [468:256] Performing reverse lookup on jbcapacitacionempresarial.com (looking for 67.159.33.100)
Sat 2011-12-17 05:43:22: [468:256] D=jbcapacitacionempresarial.com TTL=(240) A=[67.159.33.101]
Sat 2011-12-17 05:43:22: [468:256] P=010 D=jbcapacitacionempresarial.com TTL=(240) MX=[mail.jbcapacitacionempresarial.com] {67.159.33.101}
Sat 2011-12-17 05:43:22: [468:256] Spam Blocker A-record resolution of [100.33.159.67.L2.APEWS.ORG] in progress (DNS Server: 192.168.1.3)...
Sat 2011-12-17 05:43:22: [468:256] Spam Blocker D=100.33.159.67.L2.APEWS.ORG TTL=(35) A=[127.0.0.2]
Sat 2011-12-17 05:43:22: [468:256] L2.APEWS.ORG LISTED
Sat 2011-12-17 05:43:22: [468:256] --> 250 , Sender ok
Sat 2011-12-17 05:43:22: [468:256] <-- RCPT TO:
Sat 2011-12-17 05:43:22: [468:256] 'Recipient unknown' given to divert future spam
Sat 2011-12-17 05:43:22: [468:256] --> 550 , Recipient unknown
Sat 2011-12-17 05:43:23: [468:256] <-- QUIT
Sat 2011-12-17 05:43:23: [468:256] --> 221 See ya in cyberspace
Sat 2011-12-17 05:43:23: [468:256] SMTP session successful, 154 bytes transferred.