This really sounds more like at least one of your buttons isn't physically working correctly, possibly caused by the radio being dropped/moved about while in the post ?
- Have you tired connecting to a PC to see if you can remotely operate the scanner?
- Are you able to diagnose exactly which button(s) is not working? Is it all of the buttons that sit proud of the front panel?
At this stage, and based on what you've posted, I'd be taking at guess that the micro processor board has become misaligned/detached from the bits that connect to the buttons, and it's going to take some physical work to open up the scanner case to see if a fix is possible. But I'd recommend try the above steps first of all.