someone please explain this to me before I hurt something.

Chegg the bookwebsite charged me 79.89 on the 12th, I told them on the 12th because I saw when they did that that I did not authorize this so refund me before I slap the shh out of them, in the nicest way possible. I go on my paypal and it says they refund the 79 dollars YET yesterday they took it out of my Bank account. Why? Someone tell me why? I better have that money in my bank account tomorrow, or someone will be punished.