Support says they can't do anything. But I need a new steam client key

My steam client key was accidentally used on the wrong steam account over the weekend because of a mixup. It wasn't an issue over the weekend because steam allowed you to play for free so I could still launch the game. Now, I cannot start the game through my steam account and need a new steam client key to play the game.

GGG support has been immensely unhelpful as their reply is that they can't do anything... So I am wondering who can help me in this dilemna then if GGG themselves refuse to. Steam support is also not able to help as I didnt get EA through their store page so they have no records and do not understand that I just want to launch through their client.