Very very bad service

Went to the spar to buy baby formula cashier(Khosi) took the formula from a shelf that displayed R61, 99 and when she punched it on the system it was R84,99 she was also surprised as I was cause we were under the impression that the milk was R61, 99. I said I'm not going to pay R84, 99 she called her supervisor and supervisor was so not interested she just told me that she won't be able to sell me the milk for that price and she said the cashier must call the manager. Told manager the whole story and right there he told me that he will not give me the formula and he fixed the error on their side in front of me, putting the milk under the right price tag. I feel i was undermined by this manager and supervisor. Never again will i shop there!