I had something similar happen to me when I failed to give the company a 5 star.
In my case, the primary problem was with the seller. (not shipped by amazon in this case).
The day I ordered, they charged my card, and generated a tracking number with UPS (or USPS, can't recall which it was). However, that tracking number remained at "waiting to receive item from shipperr" for a week and a half, then ups/usps switched it to "undeliverable, item not received" Then the Amazon computer told me I'd get a refund. So, I started shopping around elsewhere, and a couple days later, ordered from elsewhere. Then suddenly the item from Amazon was shipped and on the way. This was a $200 product, and I did not need 2 more of them, so I had to contact the 2nd one and cancel it before they shipped. And I complained about the poor shipping provided by the seller in my review (My view is that they should not generate a tracking number and claim it was shipped until they are actually shipping the product)
In addition to that, the product itself (a SAS controller card) was DOA when it showed up. It could not recognize any disks are attached. I did some research, and realized that the card was probably pulled from some server or disk enclosure that used specialized software that required the cards firmware be disabled. So, after a weekend of agonizing over it, a bios flash, and using a disk-utility allowed me to re-enable it so it would see the disks, and afterwards it worked. So I put a note about that in my review as well, as a warning to other buyers what may be required to get it working (and also potentially saving them from sending it back themselves). Also indicating the card was unlikely to be "new" if it shipped with such a configuration. (I did not expect the card to be new, as these were older server products from a few years ago, but shoppers may have expected it to be)
All in all, I gave them a 3 star review, because of all the troubles they put me though in the whole process. In my world 3 stars is "average".
The seller contacted my directly, offering a refund if I changed my review and removed the complaints. Well, in the first place, I did not believe they would ever refund my money. And secondly, I would have felt dirty if I "sold out" like that. So I left the review as-is, and ignored their dozen follow up vaguely threatening emails urging me to change it. I did, after all, explain in my review that I did finally receive the product, and was able to get it working (after much effort). So I think that was a more-than fair review.