Sounds to me like someone permanently banned you. You would have to contact the site directly and inquire as to why. Could be something you said (or how you said it) or it could be just someone was being well obnoxious and decided to ban you. Wouldn't be the first time I have seen someone abuse power on forums/sites. Contact them and inquire as to why, let them know the date, location, etc., of your post reply and have it looked into. You may get your access back and the other person lose some of theirs, or you may not get it back, but can't hurt to try at this point.