Sorry Savinay for the late reply. While you posted this issue, I was away for a business purpose and so couldn't reply you, instead just accepted your post from my mobile. But I think I have send some suggestions to you as a reply to your private message, right?
The guy who hacked your account might be smart enough to fool you. Means, most probably he hacked your mig33 account through phishing (process of an attempt to acquire username/user-id and or password through sending fake emails to someone and by misleading people using different techniques that they are from authorized authority). Most probably the hacker who hacked your mig33 chat room might have accessed your mig33 user id by cheating you somehow and changed the ownership of the room to his id. Or else the hacker might have used some XSS vulnerability of Mig33 chat system and might have got the permission of your mig33 chat room as an owner.
In your case, if the hacker might have hacked your mig33 chat room through phishing, you can prevent it further by understanding and sharing the knowledge and your experience about phishing with others. I have already wrote a very neat and clean article about How to protect your mig33 ids from Hacking
. You may read it at-least twice and understand it. If you have any doubts, feel free to ask it to me.
And if the hacker has hacked your mig33 chat room through some XSS (cross scripting) vulnerability (security loophole), you can't do anything, the mig33 team has to be alerted and only they can help you in this situation since to prevent such actions should be taken from mig33 server side or from their administrative back-end and nothing we can do from the client or front-end side. You must immediately inform this to some mig33 staffs or admins even though most of them are quite useless. As per my experience most of the mig33 staffs or admins don't wish to hear such experience of the users and mostly in forums and all, people just ignore such issues as just the problem of the clients or mig33 users and they mostly says that the hacking has been done only through phishing.
Now a days many mig33 tools are available in the market for around 10$ which can change the room ownership. You can't do anything with this. Only mig33 staffs can fix this security vulnerability. However if your room has been hacked by this method, the only thing you can do is just contact mig33 by sending an email.
Please know that educating mig33 users is very important. I have shared most of the things with you and if you believe that there is something important in this post, it's a good idea to share this post with your friends and educate them to be stay safe from any mig33 hacking attempt. Sharing is always caring! Wish you all the best.