Poor service

The cashier's in this garage are very rude and so impatient with customers,the last straw,I went back again on Tuesday wanting to buy airtime,she sat there and we don't have change of a R100 note and I asked does that mean you won't serve me then she said yes,I'm really disappointed with service there,they need to be taken for training,cause clearly that lacks,they don't know what CUSTOMER SERVICE IS