I cannot delete an app that will not finish downloading

Hello,

I downloaded an app from Appstore and it won't finish downloading. I attached a screenshot of it

It keeps saying "installing" for a few days and I don't know what else I should try to at least uninstall it if I can't make it install. I feel like I have already tried everything. I tried uninstalling it by clicking the "X" button, from App store, from Finder>Applications. I even tried what someone suggested on another thread:in Finder>Applications>Utilities>Activity monitor I forced quit appstoreagent, storedownloadd and dock. Nothing works! What should I do?