I know neither the OP or Pewpeww, so can only say what many have said here. Make certain you have all the i's dotted and the t's crossed before joining a PUG for things of this nature. I don't understand why you wanted to go last because what you wanted hadn't dropped yet except that it seems you had no intention of sticking around to keep your end of the deal Linh. Nor do I know why you didn't understand the words "CHANCE TO LOT" in exchange for YOUR SHANK.
I would like to point out though that on the FFXIAH forums, I noticed that this Pewpeww is now offering to buy KS99 orbs. He isn't saying for how much, and only says that people will get a chance to lot BB items from HQ Kings when his LS does them. The word chance is key word here because BB drop rate is less than 100% from Kings and most definitely less than 30% from KS99's. My interpretation is of course that he is going to take advantage somehow simply because of the use of the words "chance to lot" in any deal he makes. I can see many people might mis-interpret this statement.