Voice activated calling via Bluetooth head set

[durai2710]

I am having problem with making voice activated calling via Bluetooth car hands free set without internet / date connection. Till lately when the screen is locked (when the phone screen is black) I could make voice activated calling and when I press the phone indicator on the headset and the phone will read " Say Call followed by a name or contact) but now this feature is not working instead Google Voice gets activated and requires internet connection, Is there a way to still make calls as before without requiring internet connection or an app that will do this .

I am using a Sony Xperia M2 Aqua, not sure if the recent software update made this feature redundant,
Please can someone help