key will not turn in ignition!!! car doesn't read the key! the battery is new! replaced batterys in key! the key seems to be from another benz the back up metal key for the doors don't fit the car doors. and the key wont unlock and lock doors. key seems alittle old. I don't have an extra. car is at the shop waiting on my approval to buy the sam module. they say the car wont let them diagnose it. with their benz star thingy. total charge would be 640$ for that to be put in but they said they don't know it might be one link in the chain they need to fix. im out of money if I choose to spend the 600. but I also called at a local tech from an mb dealer. and they said if the sam module is bad it might not let the key start... any help please please please