The buyer accused the seller of sending the product to him that was not suitable for his device.
However, when the seller asks to verify some information, he will refuse to provide it.
He would say that he believes that providing this information is not necessary.
Even more ridiculous is that he said when he searched for related products. The seller sold the product in the first one, so he bought it. So not applicable is the seller's fault.

For anyone who has brain knows EBay search engine works like Google or any other search engine, it will do Partial match when you searching.
For example, when you search "Dell Latitude E6400 Battery ", it will also show you the item tile that only has “Dell " or “Battery".
That means the battery for other model may also included in the search results. You still have to read the listing.
for example if your laptop is Dell Inspiron 1255,when you search "Dell Inspiron 1255",the “Dell Inspiron 1525 battery” may also in the results. and you buy it,that is your own mistake.

When the seller asks you to provide relevant information, all you have to do is provide the corresponding information. Whether this information is necessary or not is not up to you. The seller asks you to provide this information naturally for their reasons. No one will waste time on worthless information.

Refusing to provide information will only make you look more like a fraudster。
Why？
For example，the seller's listing says Dell Inspiron 1525 battery, and your laptop is also Dell Inspiron 1525,you buy it,and the battery won't fit,when seller ask what is your laptop model,you directly send a picture of the information label on your laptop,that could prove you buy correct item,the fault is on seller side,so people who are telling the truth would eager to provide evidence to backup their on story.
But If you refuse to provide information, it will only appear that you are hiding your fault.you know if you provide relevant information, it will overturn your original statement, so you dare not provide.

Why the hell you think you can come and Blaming the seller for doing the wrong thing ask for refund , but you are not willing to provide any information to prove that you are telling the truth.