No idea when it will be fixed. There was an exploit that was allowing people to sell junk items to buy shops and essentially drain people's zeny. So its disabled until its safe again, other wise you're at risk to loose your fortune without acquiring anything.
That is really odd. I hadn't heard a thing about that happening and you would think there would have been mega waves on that happening. It always worked fine when I sold to them so not sure how it was bugged but thanks for looking out for all our zenny