theres little mirc software can do depending on the network you are and what options you possess regarding your status as operator in that channel and on that specific channel.. if you cant find the person who got you opped look for the help section on the website of the network
In addition to the previous posts and depending on the type of ircd your network is using you could always try the /msg chanserv unban #channelname me commands failing that try the networks help channel