I have a 2002 SLK 230 Mercedes Benz and i recently changed the battery which locked my radio. I called Mercedes and they gave me a code by looking up my VIN number and when i press the code it still doesn't work. Am i entering the numbers wrong? Is there a certain way to enter the numbers? I don't want to go to Mercedes and have to pay for them to remove the radio to get the serial number.

Thank you!!