Most ********* company to deal with

I rented a 2 bedroom from apartment box in umhlanga. I signed a 1 year lease from 1 November 2018 to 31 October 2019. Due to restructuring in my company I have to relocate. I gave my 20 days notice as required by my lease agreement. They company is charging my R16 000 cancellation fee (2 months rent). Although this is stated in my lease the reason for my cancellation is not by choice. This amount is exhorbitant. Apartment box has no sympathy and are not willing to compromise or even allow me terms over which I can pay the cancellation. Further to this I had paid R8000 refundable deposit when I moved in. I have now received an invoice for R5347. R250 for admin fee (I have no idea what this is for), R650 post cleaning fee. The apartment was not even cleaned when I moved in. R1450 for replacing a light bulb and switch. In which world does this cost so much. Finally R2300 for prep and paint. There’s 1 mark on the wall that can be wiped out. Do we just continue to allow these people to take advantage of us ? Is there any sort of solution to prevent companies like this from bullying us and robbing us ? Please help