BlackPlayer does scrobble. You have to go into the player settings under metatag and set it. Not that hard. If you have hard time then contact BlackPlayer support  because I have scrobbling through BlackPlayer since I bought the app. Best player on Google Play that actually has no issues with this app. I just stopped using last.fm because it sucks so bad  and using libre.fm now. No ads and no nagging to pay for a subscription either.
November 25 2016