Worst service from the Checker admin manager (Maria)

Since covid I started using the 60 app for my groceries. but I have noticed with concern that checkers put the Buy 2 at a discounted price or bundles. And obviously that is what we look for in these economic conditions. Last time there was a 30% off for liquifruit drinks. The app allows the choice but as soon as you confirmed payment you get a notification that you can only get two of which you then forfeit the 30%. This has been happening for a while. Today I decided to buy protex shower gel for a special of 2 for R78. As soon as I paid the same thing happened, got a message I can only get 1 and it reverted to R50. I decided to return it to Checkers Kosmosdal because its close to me. This Checkers has always been the worst when it comes to customer service from all the checkers I have ever been to. Im sure you will get better treatment at a remote ****a shop, not this Checkers. The admin manager(Maria) there was rude saying I should have returned the item with the driver who delivered. I asked her how because they dont carry anything to document what you are returning and the online option has never worked.She told me I cant return online things at the Shop I can only return online and she was also not willing to at least allow me to take the second shower gel at the shop to qualify for the special despite the fact that they also have the same special instore . She was unwilling to even look at the invoice although I even used the checkers savings card proving i just bought there. The fight probably lasted close to an hour for something I believe was easy to solve All I was asking was for her to allow me to buy the special which is also in the catalog. She ended up refunding the R50 after a long fight. My frustration is I cant understand how this is possible that something bought online at Checkers cant be returned or exchanged at the shop even when both online and shop has the same special. and why is it that the app does not give a clear process for returns. And to be told I should have memorised the name of the driver who delivered or just give the item back to the driver. This checkers has always been rude. It is difficult to get any kind of customer service there