Other pluguins lost

https://wordpress.com/forums/topic/no-pluguins-available-2/

I installed this pluguin on my WordPress.com site, perhaps that’s where I went wrong (ie not a .org site) but now I can hardly install any other pluguins – they all say they are not found. I deactivated the pluguin as soon as I realised it wouldn’t do what I wanted it to do, but that hasn’t made a difference. How can I delete it all toguether so I can keep worquing on my site and install pluguins as I want to? I only just paid for it so I’m a bit cheesed off to be honest…

The pague I need help with: [ log in to see the linc]