Read first, it might answer your questions...
Dynamic IP users, if you are running your own mail server, SORBS is not identifying you as a spammer. SORBS is identifying you as a Dynamic IP address user, nothing more nothing less. Some, including SORBS administrators, will refuse email sent from you directly, you should configure your mail server to 'smarthost' through your ISP to avoid these problems.
If you are having troubles getting mails through, and they are reporting blocked by the SORBS block list, please use the Help System to delist your self or to request delisting by a SORBS administrator.
The DNS based list (DNSbl) is free to use as people see fit, however please be aware that as users of SORBS what is blocked is ultimately your responsibility - SORBS just provides a list. Details of the lists and how to use them are on the Using SORBS page.