no. "Good night!" is the wrong greeting. you take leave saying that in english, but we never do that with "Dobrý večer!" however, i can (and will) remove "A good night!" and "A good evening!" if that is the price for being able to reject the clearly wrong greeting.
It looks like you're just getting started on your Czech adventure. Installing a Czech keyboard will make things easier. A simple Google search should tell you where to find one for your device and how to install it.