When I had the same problem. Simply unplugging the electric power cord from the wall socket, immediately solved the problem.
Good Luck -
Sorry to hear that unplugging the cord didn't serve to unlock the lid, the way that it did for me.
Have you considered the use of a can opener ?
I think you need to contact loacal tech or service center of LG to help you out with it.
Hey there PaoloTupaz-
This post is from 2013, please don't respond to old posts such as this.