Hi this means just what it says, your IP is blacklisted. If you have a dynamic IP simply reset your internet connection and obtain a new IP (hopefully it wont be blacklisted also) If you have a static IP then inform your ISP as they are the only ones that can assign you a nice new clean IP
One thing you may be able to do is follow any instructions or whatever that may come with the ban notice, Failing that check your ip against some DNSBL lists and see which blacklist you are on, you may be able to find a link to unlist your IP