If you really think they have breached the contract or you have more classes, you can call the industrial and commercial department for arbitration.
PS: Don't go to that place for classes in the future. Just a bunch of liars. They are quite rogue in dealing with students' dissatisfaction or refund of fees. The so-called teachers they recruit are all normal students who have just graduated or haven't graduated. You can find one privately, which is many times cheaper.