Honestly, it takes considerable force to break the S Pen. They're pretty much too light on their own to break from a fall. For this to happen, your pen would've had to have been caught half held inside the phone or something else while it struck on the exposed area. This is very unfortunate and I'm sorry to see this has happened to you. As others have said, there are alternatives available online, however I'd read the compatibility very carefully to ensure it'll fit your Note 20.
