I know most people don't know this but you are supposed to have your own radio unlock code. That way when this happens you can unlock the radio yourself. In the case when you don't have your code you will need the help of your local dealer. The parts department should be able to help you with this. You will need to pull default codes from your radio - the parts people can help you with that. The dealer will then call A/C Delco and with the proper passwords and your default codes A/C Delco will give them the factory unlock code. That code should unlock your radio. With the radio unlocked use the information in your owners manual to program your own code in the radio so that this will not happen again.