Bad service by the supervisor and cashier

Good day I am really disappointed at the service I received at pick n pay at eyethu mall I asked for cash back after recieving my cash back I asked to buy airtime the cashier by the name of Tshepang mosia gave me the worst attitude he asked me why I didn't say I also wanted airtime I Should have told him to do that when I asked for cash back I said okay just give me the airtime he processed the transaction after that he told me he didn't have change while I saw that his got the change I waited while he was helping other customers. He then called his supervisor because he wanted to void the transaction he made for another customer after some time he gave me my change while he was doing that he gave me the worst look I asked him why was he looking at me like that its then when I asked for the manager he just showed me the supervisor I told the supervisor of what I had encountered instead the lady just told me its unlike him which made me more furious because I expected her to calm me down and deal with the situation in a right way.what a bad service I received. I dont even think comfortable to even shop at that store Anymore.