I had this same problem with my Level. I had only put about 150 miles on mine when I couldn't get the key to turn to lock the battery. Thankfully it was stuck in the unlocked position, as I was able to pull the battery and see the lock setup. I took it apart and discovered the problem. There is a retention screw on the lock cylinder that got stuck in a channel on the cylinder. I was able to back the screw out and reset it, good as new.
I don't recommend doing this unless you are good with tools, good with disassembling and reassembling things, and are aware that this *might* void your warranty.
I can't help but tinker, been taking things apart and reassembling them my whole life.
If anyone is interested and if it's ok with the forum rules I can post some pics and details of how I fixed this.