Try to do this:
getSupportActionBar().setDisplayShowTitleEnabled(false);
getSupportActionBar().setDisplayHomeAsUpEnabled(false);
getSupportActionBar().setDisplayShowTitleEnabled(false);
and if you made your custom toolbar (which i presume you did) then you can use the simplest way possible to do this:
toolbarTitle = (TextView)findViewById(R.id.toolbar_title);
toolbarSubTitle = (TextView)findViewById(R.id.toolbar_subtitle);
toolbarTitle.setText("Title");
toolbarSubTitle.setText("Subtitle");
Same goes for any other views you put in your toolbar. Hope it helps.