This is actually infuriating. This used to happen to me constantly but I sold cheap items for £15 that cost me £3 per unit so it was easy to forget. Sadly this is completely unavoidable on Amazon, even more so now that the eu and U.K. have made it law to allow a buyer to return electronic items for up to 1 year since purchase if it becomes defective (which Amazon will not check). This means that buyers can randomly returns items for up to a year from purchase. I’ve had one happen from 2.5 years ago as a personal best
They recently refunded a customer because the “wrong item arrived” I only have one SKU. They have lost over £1500 of stock that they won’t reimburse me for because it’s older than 6 months from the invoice date, and lastly, their system failed to update a despatch status (I did update it) and have refunded a customer for an order I shipped and they received. Amazons advice was to contact the customer and ask them to purchase it again, however when they cancel an order, you can’t see the customers details, so they have stolen/given away my products. Dealing with Amazon is seriously and honestly having a detrimental impact on my mental health. FBA sounds wonderful but it really feels like Amazon has done everything in their power to destroy my business. How other sellers work with them I don’t know, it is just not commercially viable to work with them.
I’ve come to the conclusion that you’ve got to sell fairly low value simple products and kits stump the loses. Therefore you need popular high volume stuff with a decent margin.
Fortunately 99% of my sales are through my own shop. I basically just use Amazon for fulfilment.
Although I do plan to put more lower value items into Amazon where I wouldn’t mind if the odd £10 or £20 item went missing.