can you help please.......my GPS works but dont give me the right position and the phone was working but now no phone ......when to chevrolet they say need to change the modul at $700.00......I did try alot of thing but stil......I am in Canada montreal.....pressing the button nav....give me Edmontton need to change to Quebec and so on......but now the screen appear but say no GPS and PHONE.....can you help....thank...