One: You do not need to trade with the mules. You simply put the items in the company box and they can pick them up from there
Two: No one said anything about people.. if anything those are poor bastards. It is about their policies, processes and procedures which are all shit and prevents them from acting quickly
Three: My strategy with that dipshit is simple but frustrating.. figure out his breaking point, post the item at it with his price + 1 gil, let him take the shitty sale and up your price again
You may sell an item or two at a low price (never at a loss because their breaking point is almost the cost to make + around 10,000 gil)
It has been working well and is somewhat satisfying but it is very exhausting and time consuming