Enable to remove SharePoint 2013 apps

I installed some ShaPoint 2013 apps from the Sharepoint Store and I am not able to remove them. The first problem came after forcing the application master pages, the server administrator launched an installation which forced all the site collection (including application's pages) to use a custom master page. I was not able to manage my applications so I decided to remove them.

Using the custom remove button doesn't work and the applications show :

But doesn't remove the app. I waited for some hours but still showing the same message :

We're removing your app ...

I tried to unisstall the apps using powershell but that doesn't work.

Is there a way to force the unistall ? Is it possible to manage these apps from the central administration ?