Drone Tactics Save Delete?!

Heya AllI‘ve downloaded Drone Tactics a couple of days ago, but lately if i save my game and turn my DS off, then later i turn it on, it has deleted the save file...
Do i something wrong, or must there comming some new R4ds file, or must i buy the game???
hope i've send enough info, because im typing on my Wii :)

You can try reinstalling the firmware. Or delete the save file or see if there's any corrupt files on your MicroSD.