Hi all firstly sorry if going over old ground with this just getting nowhere fast win this problem !!!

i have a 2006 q7 mmi 2g, with factory bluetooth etc. ever since had the car the Bluetooth will cut out and reconnect some 30 secs or so later, I then fitted a cradle to the prewired armrest for iphone4 and boost signal great but will only charge for 5 seconds when mmi starts up and then stops
has been to main dealer and all they could come up with was could be the module
thanks for any replies