CTU Online - AIU Online - CTU is making me pay for thier mistakes. Internet

I have been attending CTU now for a little over 2 years, I have found the education to be quite good and the instructors to be very fair, The problem that I have is the fact that I have just recieved a bill from CTU and they have withdrwan me from the campus becaause they say that I owe them $4000, I have never before had a bill with them because my tuition is payed by my student loan lender, well this time they said that they couldnt recieve payment from my lender because my MPN was out of date and since they had slready reported me as withdrwan from the school the lender couldnt send them any payment, I told CTU that I had signed all the paperwork that was given me to sign by the finaincial aid department, and that If my MPN was out of date then they should have notified me so that I could sign a new one, which they never did, all my status said was MPN on file. So now thery are comming after me to pay this money. They have been herassing me nonstop with emails threating me that they are turning me over to collections, now Im sure im not the only one these people are trying to scam, from what I see they are pretty good at it, I want to get a bunch of us togetehr and file a class action on these Jokers. Please contact me at (((ROR REDACTED))) if your interested..and pass the word that these people are shisters!!