I have a 2014 Mazda 3, mid line trim level and for 2 years my Bluetooth has worked for both phone calls and audio streaming. The other day, the audio stopped working. I can still make and receive phone calls.
I've already rebooted the phone, unpaired and then re-paired the phone with the radio etc. Any other ideas?

 

Get someone else's phone and pair it to determine if its the phone or the car.

 

Maybe it is the bluetooth issue, I'd suggest you turn off the bluetooth function on your iphone and then try again.