Realife stories - planned obsolescence of refunds' receipts

2018-6-20, typing started a few days ago.
A month ago I bought 8 packs of 0.5kg cocoa among other things.
I bought so much because it was very cheap.
After I tried it, I discovered that it is spoiled: its color was very light, and after stirring it remained light and did not yield the taste and the color that cocoa should give when stirred with milk.
It got oxygenated in its pack.
It was packed hermetically, but with a lot of air which I assume may have been moist.
I retrieved 7 out of the 8 packs to the supermarket and got a refund receipt to be used in the network for purchases.
When I found a token gesture of an opportunity to use it, I discovered that the print was washed off despite it never got wet.
It was in my purse which was dry.
The print's dye is intended to wear out fast, so that people will lose their money.
The manager of the store did not deny that it is possible that I lost my money.
Everyone including her said that it will not (they all claimed that it is impossible) be replaced with a new refund receipt.
I call it refund receipt, but I clarify again: It is not meant to refund, just to purchase at the same amount, which I do not complain about.
I complain about almost losing my money (most readers' reading comprehension or at least their attention is lacking).
In the end they manually worked it out, after the prime cashier made a blatant error in her rewriting of one of the digits, which was still clear enough for me to figure.
In the end, I got my money's worth, but was close to losing it due to corporate evil (not a communist, a capitalist or an anarchist here, I just strive for justice).