Deposit Witheld without valid reason

I was renting a flat owned by maxprop in durban, I moved out on the 30th of January 2015. A few days later they paid a portion of my deposit and witheld some of the money. When I questioned them about the remainder they said they were waiting for the electricity statement and that they would pay me the remainder of my my deposit once they have settled the electricity bill. Up to this day they still havent paid.