Mistreatment of Loyal Customer

I have been a loyal customer for over twenty years. Recently I experience such mistreatment that I am considering changing banks. I dont always draw cash at the tellers and had to due to unfortunate circumstances. Upon entering Mall of the South Standard bank, I was told that I should use the atm but when I requested to use the Tellers the lady at enquiries directed me accordingly. The teller inform me that he could not assist me as its the policy of the bank that only withdrawals of R10 0000.00 are allowed. Thereafter I requested to see the manager but I was told that I will be assisted however there would be a penalty fee for drawing the cash. I was charged R300.00. There are no signs in the branch stipulating that tellers will not assist withdrwals nor limits of these withdrawals. Furthermore a standard bank staff member completed a deposit of R600.00 at the tellers. South Africa is known for its crime especially ATM theft. Why should customers be penalize for choosing the way we draw our money? Standard bank should place proper signage if the bank chooses to not provide a service to its customers