Bank treating you like a ********

For the 6th time i have struggled with FNB after someone purchasing a vehicle from me! A big amount of money was paid into my account by a customer buying a vehicle from from me on Friday morning. It is now the next week Tuesday and yet not received my money!! The client and i have contacted both our private bankers a few times and the money still hangs only in the balance yet not available balance??? Throwing a happy trade to the ***** department handling me and the purchaser as *********. After requesting a bank stamped letter it still seemed right to FNB requesting another letter stamped by SAPS and yet still not received my money?? Is it really wort steeling from one banker as you are First National Bank?? Surely i am not the only one suffering this incident as you have awnsers to everything being asked to avoid being suspected!! As soon as i get my money, i will transfer from bank as well as everyone i know i can convince not to be held by your high bank charges and cant even receive money that is rightfully their's