Biology PhD program appeal meeting

Hi everyone,
I’m in a bit of a situation in my graduate program. I’m almost done with 4 yrs of the PhD, and I was asked to either leave the program or appeal the decision to leave the program. Here’s the thing: I worked with my PI for a year, left the lab because it was no longer a good fit, rotated in a few labs (during my 3rd yr) that didn’t work out, and went back to my original PI because I was told if I don’t have a supporting lab then I would be kicked out. I tried to resolve my differences with the PI, but things were still somewhat unchanged, such as the PI’s condescending and disrespectful attitude towards graduate students. I was like “forget it”; let me just ignore those issues and just work my butt off to generate data and help with the manuscript. I did that for half a year, and the PhD program director says that I need to be evaluated by a committee to judge my progress to see if I should stay. During the meeting, before I even presented my data, I was asked to leave the room. Apparently, my PI had told the other committee members my story and biased them against me in such a way that when I re-entered the room, they looked at my with a nasty face. I did my presentation, which was a PROGRESS meeting, and the committee members asked me questions left and right. I answered to the best of my abilities and they wrote a report indicating that I have little knowledge of general biological concepts. I don’t understand how that’s possible if I’m second author on the accepted manuscript! I worked my butt off all for administrative and political nonsense. I’m just trying to get my PhD and get out of there. I knew the PI was biased and did not like me because I had left the lab previously. I asked my PI if I could get a recommendation letter at least so I can apply for a job in case I get kicked out, and the PI’s response was “You didn’t really do much. I’ll write you a letter, just not a good one.”

Now, I have an appeal meeting where I was told that I have to write a statement of justification that provides a clear plan for moving forward with a mentor willing to support my thesis research. I also have the option of meeting the committee in person too. I’m working on finding a new lab to the best of my abilities. My issue is I am scared out of my wits. I worked very hard and all these damn professors are giving me a bad name. What do I write in my appeal justification letter so that I have a higher likelihood of staying in the program but without looking unprofessional? Really, it’s very clear that the committee was biased because of my PI, and they are the reason I can’t even finish my degree! I have a publication out of my work, for God’s sake!