I’m not sure what experience you’ve had but eBay does quite well on buyer protection. Same goes for Swappa. Can’t speak for either website in non-US countries though
I have this exact one. You need to find a module that’s exactly the right spec as I tried one with faster speeds and it didn’t work.
This is the one I got: https://www.amazon.com/dp/B07NZSKNBD?ref=ppx_pop_mob_ap_share
ITT, people giving quotes but not saying from what movie