Earphone calls instead of next song

Question

I've bought Plantronics GO bluetooth earbuds and when I double-click them (next song) it starts calling my last call.

Any thoughts what goes wrong here? plantronics replied that it are my phone settings. What did I miss?

Answer 1

The plus and minus keys are for next and previous song. Double clicking the middle button will start calling the last person in the "recent calls" list.