WhatsApp on iOS plays voice notes on Speaker. How can i force it to play them on my BT Headset? I got an iPhone 5 with iOS 7 paired with a Sony DR-BTN200 headset. Whenever i get a voice note on WhatsApp and i play it back, music pauses on my BT headset but the voice note is played from the phone's little call speaker (Not even the loud speaker) so it's pretty hard to listen to them. 

Any ideas on how to fix this? [Jailbreaking is out of the question as this phone has been lent to me]
Slide up from the bottom you'll find "airplay"  tap it and select iphone speaker