Bought the wrong laptop battery

I bought the wrong battery from Subtel, though this could happen when buying from others as well:



Subtel article number 940496 was listed as compatible with several Dell laptops, including mine. When it arrived, I discovered that it didn't fit in my laptop physically. When I wrote to Subtel, I made the mistake of using the word refund/cancel. They told me to order shipping and send the receipt by e-mail and then they'd refund me. I should have written that they made a mistake when listing the battery, and were therefore at fault, and I need a refund.

But I started researching shipping, and found that: Laptop batteries not installed in a laptop can not be sent by regular mail/shipping. It can only be sent by courier, which will cost more than the battery does . No doubt Subtel knows this, and this is one reason why Finn and other marketplaces are overflowing with ads for laptop batteries. Except they need to be physically collected by the recipient, not sent by Fiks Ferdig or other mail solutions. Subtel themselves send batteries at scale and have special ways of doing it that a private person does not have access to.

I was in a quandary. What to do? Support told me it was the wrong battery for my particular laptop, and this is why it doesn't fit. It was meant for a model that has a SATA drive in addition to the NVMe drive, while mine only had the NVMe. Support did not know that these machines are convertible. I could turn mine into that other model. Which I planned to do, until I found a better solution for my Linux drive. In other words, that size battery was FULLY compatible with my machine, despite what Subtel told me.

This told me support is not all knowing, so I had to figure this out myself. Here's my method:

1) The battery had been listed as compatible with the Dell P56F002 battery. There's a compatibility tab on Subtel's website. To be sure you have the right battery, go to that tab and check the Dell (or other brand) number. Follow the link and make sure it points back to the page for the battery you are considering. If not, there's something wrong.
2) The better way is to start with the number on the battery you're replacing, or the number on your receipt. Then see which batteries are listed as compatible with that.
3) Look at the photo, and check the battery in your machine, that the configuration is physically compatible.

Turns out my battery was ONLY meant for Asus laptops, not Dells. They have since removed the Dells from the compatibility list after I complained. They refunded me after I proved I was not the one who made the mistake, and told me to keep the battery. And I can not get rid of it. It has to be collected in person...