Audi music interface issue

Hi,

I have an Audi s5 and when I plug my iPhone 4 in to the glove box it does notload my music. It does charge the phone, and I can connect via bluetooth for my contacts, but no music. t looks like it is connecting but it just keeps falling off. I have tried with y friends phones and some work and some do not. it is very odd!

Can anyone help?

Thanks,

Jon