Hello, it is possible that if you use a shared IP address, someone who has the same ISP was recognized as a spammer, which caused blocking of your computer as well.
There are two ways to remove the ban - go to your database and delete your IP address from the table "wp_sb_ip_log" (permanent solution) or change the name of the plugin's directory on FTP, which deactivates the plugin (then execute the first step).
If you do not want to to be banned again, please muse the fast method of detection of spammers, which will sent you a cookie that will tag your PC as not spammy.
I am working on a new feature which will allow you to choose between blocking or just disabling comments in the next version. It will be released in 2 or 3 months, please be patient.