Whakano in heist

Whakano in heist place says that he's got a few contracts to offer for sale, but his inventory is empty . I was able to purchase them only one time . He doesn't sell them daily ?

I also have unrelated question , can exalted orb be used on heist gear ( cloak, brooch etc) ?

I think he refreshes his inventory when you level up?
Or something like that