I'm not sure who/where to direct this. However, I was unable to log into the official Witcher forum after not logging in since July/Aug of 2015. When I do log in it says:

You have been permanently banned by dragonbird for the following reason:
Offering to provide pirated version of the game.

This is absurd. I don't pirate software. I have enough money to buy what I want. The game was relatively cheap in price when I purchased it and the price has dropped since then making it easy for someone to pick up the game without the need to pirate. I had no idea that my forum account was banned until I attempted to log in. I haven't played Witcher 3 since 2015. However, with a new PC built and updated graphics card I wanted to install and test the game with the new hardware. I need to get the patches/updates for the game, but no patches are listed for download on GoG.

Where/how do I get the patches for download and how do I go about getting my account restored on the official Witcher 3 forum?

download it all from scratch

I don't remember how it works exactly but I think you can redeem a code that came with the game on GOG and then you'll be able to download patches from GOG.
Do you even need a Witcher forum account to download patches? I've only ever used that site for W2.

P.S. The 'reason' for banning you doesn't say YOU pirated any software. It says you offered to distribute software. It has nothing to do with whether you bought the software or not.