Wow, that is crazy. I had about a one week wait time from sending the letter to it showing up on LSAC. I would not tolerate a 20 day wait. I would call LSAC. They were very helpful when this kind of thing happened with my transcripts. The person I spoke to gave me their contact info, so I was able to mail it direct to him and then it was taken care of within 2 days.
Definitely call LSAC and see what the hell is taking so long.