I bought the plugin called Auction House
Proof of me actually buying it:
http://i.imgur.com/MvPAVwX.png
And i didn't receive it (wasn't added to the list i suppose).
Proof of not able to download it/not on the list:
http://i.imgur.com/cQMRan3.pn
g
http://i.imgur.com/S1FT4Ku.png

Also tried contacting the seller through email, Skype and even through spigot forums. No response. Looking at the forums threads it seems that the creator of the plugin is inactive. Furthermore the plugin is broken as i heard many times from other people.