I'm also getting the game freezing option, as well as still seeing incredibly low sales for songs. The only way to actually make money seems to be through the managers getting different deals for the idols, not actually making music :(
Hey, I just pushed an update that should fix the freezing bug.
For single sales, there's a big penalty to sales if you release singles too often (-50% if there's been less than a month from the previous single), maybe you're hitting that?
You really need to concentrate on getting fans to get sales up... Look at Promotion on the Activities screen or Details widget. Fans are love. Fans are life.