Bluetooth Music Keeps Going Quiet?

Hello there

Random and strange things started happening when I'm streaming music through the Bluetooth system. I'll start from beginning

I have 2012 Occy vRS with the Columbus SatNav unit and when I got it I have an iPhone 4s. All was fine it connected to car received calls and dialled fine and streamed music superbly. I had the sat nav voice over already setup but I couldn't get it to quieten the music down when she talked which was pointless so I gave up and turned it off.

I upgraded to a 5c in April and all has been fine until recently. I tried to have the sat nav voice over come on and I couldn't get it to quieten the music (after extensive trial and error and playing with it while out for a drive) so I gave up. I put all settings back to how they were and it was fine. Other week the music streaming would all of a sudden go quiet like a text is coming through and not go back loud once the text ringtone had finished. I would either get whoever is in the car to text my phone so it would reset itself or I would pull over and have to do it. Turning to radio then back or turning unit off then back on doesn't work. It can get real annoying as you can imagine. Anyone had this problem at all? And any fixes?

Edited 3 January, 201511 yr by Swift Chris