"***** n Pain" for a Calculator

Trying to exchange my sons scientific calculator was a daunting experience from the William Moffett pnp hyper in Port Elizabeth. Because I did not have a proof of purchase, I had to go to customer care so they can check the purchase on my smartshopper, I was assisted by Bonita who phoned head office CC, for an hour they kept saying they can't find the purchase the only purchase they see is alcohol boughtvon the 31 March, I was so embarrassed because my kids were with me, and ww knew that is not teue, as we shop at that pnp every month, I even bought a fridge in January for 11 000. After an hour they say they are offline, I then asked Bonita if I can come back the weekend and she said she doesn't think they open weekends I must rather come the Monday. I come the Monday, still no joy as they still say they don't see any purchase of a Casio calculator. I go home, and call the head office customer service number myself, and a guy assisted me, found the purchase and told me to go back to the store so they can give me a transaction number. I go back, and remember all this time my calculator was fine for exchange otherwise we wouldn't have gone through this trouble so long, in the store the lady gives the transaction number, and we look for the calculator for exchange, we only find one left but the description apparently wasn't the same so she went to ask for managers advise, Chris, who looked at the calculators, but when he saw the one im coming to exchange, he sees that it is further damaged, I was surprised too because when I brought the calculator the lcd was only damaged ot had a black mark, now when Chris looked at it, it had crack marks as well that were never there before. He just walked off and left while i was trying to explain., rude. That's when I wrote to the head office tp complain, then 2 people from the pnp say they "tried" to call me but I never saw any missed calls. What really makes me upset os that had I been efficiently assisted on Friday, the calculator wouldn't have been further damaged and the exchange would have been done, and also I found out that head office is open for service during the weekend and public holiday, so if Bonita had known this information and shared it with me instead of saying "they don't open weekends, I must come back Monday" the calculator wouldn't be further damaged. At this point its not even about me not getting the exchange its about the lack of efficient service, no enthusiasm or effort to assist efficiently, its just easier to say "the system is offline" to get rid of a customer. And what is sad is that i am a loyal customer, I shop there every month for the past maybe 9 years straight .