Growtecs Infotech - Payment not released

I was working for Growtecs Infotech , i was developing and ecommerce website for them, ** thousand was final amount decided, then they increase work and the design to develop, we were in a deal where the fixed number of design was to be developed for the fixed number of amount , but still time to time they increased their demand, and in the end where ** thousand was paid , but remaining amount ** thousand was reaming at that time they offered me * thousand for one extra module, so that means more ** thousand was remaining from their side to pay me, they promised in december , but bow its feb , and now they are telling they has some internal discussion and they forgot to tell me that they are cancelling my ** thousand from the payment