Although a clean installation of everything now and then won’t hurt, I would not give up hope just yet.

It is not only you who currently can’t access the KB site from Bitdefender.
The entire KB site is down a.t.m.

I suggest to get the uninstall on a working system.
Perhaps on a other system you have there or neighbors, friend, relative, library…

A other option is to get Farbar, run it and attach the created logs (FRST.txt and Addition.txt) to a post here.