Thermaltake eisberg install nightmare

I finally got round to installing this, I thought it seemed simple when I did until I went to mount the cooler and it would not screw down I finally managed to get one corner down and locked however none of the other ones locked in.



I decided to remove them all but the one that locked in now refused to unscrew so I used pliers to hold the piece at bottom to unscrew the locked part and it came off so I could remove the cooler from the board.



However the actual piece is still locked in I just removed the spring part on the top so if I turn the metal piece it just turns and doesnt unscrew, I tried holding the base with pliers but then it doesnt turn at all.



So I am stuck.