iphone 4 and nissan connect

Hello,

I have connected via bluetooth my iphone 4 and the car system Nissan connect, it works, nearly everything is perfect except when I click on agenda in the car system it always shows (first of the list) a foreign number which is not even in my iphone agenda, on top of the list of all my contacts. Amazing as it is the agenda imported from the iphone! I have been looking in address book app, no sign of that phone number and in the car there is no way to delete this entry, so I thought the only possible solution is through the application on my Mac or through the iphone but I don't see the number, anyone has got a idea of why this is happening? Thanks