They banned a range in which your IP is in, most likely. So a dynamic IP won't save you from that. Also, it depends on which ISP you have and which package you bought if you have a dynamic IP or a static IP.
I won't go into methods of getting around your ban for some simple reasons. First of all, those 'alternative methods' are illegal. Second, they certainly have a reason for banning you, otherwise they wouldn't have took the effort to ban you. Third, your intentions aren't correct, I won't give someone advice if it serves for what you seek. And fourth, it's their server, they pay for it and there's no contract between you and them so they can ban whoever they like for whatever reason they like.
Grtz, DePhille