What happe with customer service

My mother is 81 years old she bought a new fridge she returned it because it was too big when we went back the sales person changed her makro card to pensioner but the did not want ro give us the discount because my mother was not with us. We bought the fridge on the same day and the manager expected my 81 year old mother to come back to the store to get the discount tis is ridiculous she did not even offer us a I am sorry just we cannot help you