I have set a rule in the firewall to block port 8080 however when i go to www.mydomain.com:8080 it is still accessible and fails the PCI security check, is there another way to block port 8080?
AFAIR port 8080 is used by Tomcat. Also it can be used as proxy port for Nginx - http://kb.parallels.com/114249
Make sure that you really want to block this port and it will not break correct Plesk operation.