Just so you are not alone, played this on PS3 and Xbox, and no matter what was done your scores will keep for only, like, 100 songs. It sucks, but that is just the way of it and, I wish it was different, and it would remember all the songs, so you could play ones that you haven’t done, but whomever coded this game and the way they decided that there should be a 3000 song limit, and all the other stuff was incredibly short-sighted. I hear ya.
You are about to leave Rhythm Gaming World and access the external songs DB. While no song or file sold for commercially available videogames is hosted there and only fan generated content is allowed, Rhythm Gaming World has no direct control over the database and no files are hosted here. Alright, we had to made you aware of this, now you can visit the database!