I thought this was a very interesting vieo about the use of “huh?” or 「はぁ?」 and how many languages around the world have found a quick way to let the other party know that there has been a problem in communication.
The Japanese level is rather advanced but I encourage intermediate learners to give it a try and see if you manage to pick up a good chunk of the vocabulary you didn’t know from context as well.
It’s basically a sigh. I use it sometimes.