How many of each item do you have?
note that ramen only require "one of any" whereas the others require "x of each"
So if you have 99999 compass, 99999 map, 99932958239 flashlight and 9 pencils, you STILL can't get anything else, because you don't have enough pencils

The fine print says that exchanges are limited, thou I haven't gotten to that point yet (I got one magatama, haven't saved enough for another) so I can't tell, but is it possible that you capped on everything?