How can I get completely rid of Instapull

I am unable to remove this app and it is causing issues when I do updates, and I just want it gone, it wasn't worth the 2.99 I paid, it wasn't a deal @ free. It sit in the download folder/page and does nothing, if I retry to download it instatly gives an error message box, I've tried the various suggestions but it won't fully download so I'm guessing thats why I can't delete it. Any help is appreciated.

Michael S.