Creepy Perverted ist Janitor What Should I Do?

I usually get to lunch later than most other people in my grade because the teacher that I have in the cl before it always keeps us overtime, and when I get to the lunchroom I usually only have 5-10 minutes to eat. But then, the janitor comes up to the table where me and most of my friends sit and he tells us that we better get out of the cafeteria NOW or else he will go get the principal, who will give us all detention, and the part that really sucks is that the janitor kicks us out even before the bell rings (when the bell does we ring we go with no problem). There is already a teacher on duty in the lunchroom, and it is HER job to tell us that the bell is about to ring. In my school we also have people that help the cooks, and after they are finished they can go clean tables. One day my friend and I were igned to help the cooks, and, when you do that, you are supposed to eat lunch before you start. That day we we told too late that we had to help, so we had no time to eat beforehand. So we decided that we must eat one way or another, so once we were finished helping the cooks we grabbed our lunches and sat down with our friends. The janitor came over to us and said "no you girls can't sit down you have tables to clean" I just told him that that was HIS job (which he never does because he is *flirting* with the teachers that p through the room), not ours, and we did not intend to starve. He just walked away. Today the bell had just rang we my friends we gathering up our trash when the janitor came up to our table and said "time to go girls" which he does EVERY SINGLE DAY. I was already pretty pissed because he had freaked out an autistic girl and had made her cry, so I spent eight out of my ten minutes trying to calm her down. When he told us "it's time to go" I said (in kind of an irratated tone) "I know. We heard the bell". He told us it was time to go AGAIN. I told him that we heard the bell AGAIN. He then came back to our tabe, put his hand on his hip, pointed at me and said in a very mean tone "You really need to stop using that mouth with me, Melynda [my last name here]". I said "I didnt have any time to eat because I was trying to calm down an autistic girl that was crying" he says "I don't even know who you're talking about" I told him her name and he claimed that he never even heared of her (he knows who she is, but he wouldn't admit it). I just said "Well, you did make her cry" and then ran out of the lunchroom. Another things that really tickes me off is that he only tells the girls to leave, not the guys. What do you think of him? What should I do about it? Do you think I did the right things before? Would you consider it harment? Do you think that he even has a right to be scolding us, considering that we don't do anything wrong and he is a JANITOR not an authority? Pleas help me!