I dropped my Samsung comeback on the floor and the battery fell out and now it can't find a signal, what happened?

It's possible something was damaged when you dropped it. Remove the battery from the phone again for a little bit, then replace it and start the phone back up. If it still isn't working, I would take it into your cell company. Hopefully you have insurance on it so all you'll have to do is pay the deductible.

Thank you