In 3 weeks I was sent 14 messages saying that returns were broken. They came from 2 stores, both of them stores helping us test. The software had not crashed once. Nothing in the logs had been recorded as a failure either.
KAZENA Order is a cash register. Returns are a feature inside it, running through 4 screens in order: find the original receipt, pick the lines to give back, pick a reason, then confirm. Press confirm and the screen goes back to the list of receipts. It just goes back. Nothing is shown.
A store's returns have a limit. There is a setting, held per store, allowing them up to 7 days from the original sale. The confirm step checked those 7 days and, when the sale fell outside, finished without doing anything at all. I wrote that one line. I meant to decide the wording for the screen later, left it empty, and forgot.
The reason it never reproduced at the office came out afterwards and it was embarrassing. The receipts we test with are made the same morning we test. So the only ones ever in hand are the ones inside the limit. To have a receipt older than 7 days I would have to wait 7 days or touch the dates, and I had done neither.
The heavier half is what was happening in the stores. Confirm sits on the 4th screen. The clerk is standing in front of a customer, finding the receipt, picking the lines, picking the reason. Counted from the logs, getting that far took 2 minutes 40 seconds on average. And then the screen goes quiet and goes back.
In those 3 weeks, 31 returns fell outside the limit. 9 of them were handled without the register at all: a handwritten slip attached, passed to the office later. That is not the clerks' fault. Going around a tool that does not work, so the customer in front of them is not left waiting, is the right call. Software that stops without saying anything pushes people outside itself.
My first repair was to gray out the confirm button whenever the condition was not met. It went in within half a day. Within 4 days, 6 more messages had come. The wording had changed to the button cannot be pressed. That is worse to receive than a report that something is broken.
A gray button says nothing. Not why it cannot be pressed, not what to do instead, not what to tell the customer. The outcome is the same stop, with fewer things to go on. A button that cannot be pressed, unless it says why on its own, cannot be told apart from a broken one.
Next I moved the check to the entrance. On the list of receipts, anything past 7 days was left out from the start. As a screen, that came out clean. A week later a store told us that the receipt the customer was holding had become a receipt the system did not have.
Hiding is not explaining. A paper in the customer's hand that does not appear on the screen is worse than being told it is past the limit. A clerk can explain nothing about something that is not there.
The shape we settled on is this. Receipts past the limit still appear in the list, shown in a state that cannot be selected, with the date of the sale and how many days past the limit it is written beside them. The confirm button stays pressable, and when it cannot be carried through, the reason sits next to it. The wording was written so that a clerk can say it out loud to the customer exactly as it stands: this receipt is from August 3, and it is 5 days past the limit for returns.
In the 3 weeks after that, messages saying something was broken came to 0. 12 returns fell outside the limit, and all 12 stopped at the entrance. 1 arrived at the office with a slip attached, and that one was for a reason other than the limit.
I estimated half a day and it took 8. 2 days went into deciding the wording and the ordering; the rest was squaring the 31 earlier attempts and the 9 that had travelled on paper against the books. I sent the whole account to the engineer on the KAZENA side, who wrote back that they knew of 2 parts shaped the same way. Both said nothing at the entrance and stopped quietly at the exit. At the office now, when we add a condition, the first questions are where a person finds out about it and what they can say when they do.