Sorry to hear about your problem. I will be happy to help.
This is a known problem. The fix is to replace the optical engine. It is a very expensive part and labor is like $300. You need to contact Mitsubishi because there was a "recall" for this problem on certain models (even out of warranty). If they say it's not covered by the recall then try to get a supervisor to authorize the repair. Be persistent and polite to get the best results.
If you need further assistance please reply here to this topic, I am here to help.