It should work again if the player exits and rejoins the game. If not (or they don't want to do that), probably the only option is to break the wall where it is and if that wall is needed, such as at a base, you'd need to replace the broken block(s). If you want to just get rid of the drone, you can attempt first to use the jd clear command (see the help for that) to remove the connection with the drone and player (it won't remove the drone itself). That may allow the player to use a new drone. If not, or if you want to remove the drone, you'd need to delete the two drone files in your save folder. You should have all other players pick up their drones first. Then you'll need to use the jd clear command in the game. The player with the problem should now be able to place a new drone and the original should be gone.