ᐅ From what point do you need to have as much knowledge as an IKEA employee?

A few weeks ago, we bought a dining table from IKEA and considered ourselves satisfied IKEA customers, as we had purchased many items there before and, apart from minor issues that were not worth mentioning, had no complaints. However, after assembling the table, we noticed that the frame’s color did not match the tabletop. Oh no,... someone must have placed package number 2 in the wrong spot, and we didn’t notice it when picking it up. Well, we thought, no problem, we’ll exchange it. But unfortunately, not with the customer service staff in Oldenburg. They told me that I should have checked the item numbers, which we had not done due to lack of information. Of course, we read everything displayed on the shelf, but it only said: “Please take 2 packages!” Next to that, on an adjacent shelf where only single packages were stored, there was a small sticker advising to compare the item numbers (I checked again today to see if that sticker was actually there and took a photo of the situation). Unfortunately, we did not look there, only at the place where the goods we wanted were stored. Also, at the checkout, no one informed us that if taking 2 packages, we should compare the item numbers. So we left the store clueless, but after my unsuccessful exchange attempt, I have learned a lot. It’s unbelievable that I have now made two pointless trips to IKEA Oldenburg and was made to feel it was my own fault because I wasn’t competent enough to understand the IKEA system right away. And if no matching “pair” is found, then it’s just bad luck. I will have this reviewed thoroughly to decide whether I need to accept this. I’m curious if anyone thinks I’m unfairly disappointed. Oh, and the table in question is a Bjursta dining table.