Sales reps don't always know the answers, and they should say they don't know when they truly don't, but human nature dislikes admitting lack of knowledge, and so the rep might guess the answer, and be wrong. When talking to a rep in person, I begin my question by saying something like, "You might not know the answer to this, and if you don't that's okay, just say so..." This does two things: it gives the rep an out, which calms them, and it opens communication, which can lead to finding an answer if the rep doesn't know it.
Chat, email, telephone, yeah they're bad, but even a corporate store can have a line out the door by noon. This is, sadly, just how it is. It's not possible to have a ratio of one rep for every customer.
