My Galaxy s4 survived a fall while on bike. It is working flawlessly except the vibration has gone down. I tested with app, the motor is working but not like before.
I am sorry for your loss. You can try the RMA.
But if its costs you, you would need to think if the vibration its worth the price.
Maybe OP thought there's some self medication that can be given to the phone. But its not possible, unless you are an engineer and want to open the phone yourself.
The vibration has not stopped completely. It has gone down to minimum so I am not still able to figure out what exactly the issue is.