Bad service and customer care etiquette

Extremely poor and bad service, Staff has no knowledge about company procedures, received a t shirt as a gift, with the label still on, as per normal this is exchangeable at any retail store, but this store is so special that they dont do that with an original purchase slip, the staff member was clueless about any of these procedures, at first she said i could exchange for something else then when nothing fitted me or i did not like anything and would like the money to be loaded as credit so i could put more money and buy something else, she then called her manager and said now that no exchange can be done. Then she said she will call the headoffice on Monday 11.03.2019 and give me feedback if this is possible and then call me back, i have not received any response, and i then called in, she is not in at work, and the person i spoke to explained that i now need to call in again on Tuesday cause the regional manager will be there and i need to speak to that person, All this for a R200 tshirt exchange. The Staff does have the duplicate purchase slip printed out, cause i now had to call and worry the person who made the purchase for me to get a time and date of the purchase. If all else Fails im stuck with a tshirt that does not fit me, A hugely apologetic friend for buying a gift that cant be returned, and a happy company that still made a R200 sale !!!!