ADesire

Hello, I just bought this car yesterday and the radio is not working, the person who had the car tried too many codes and it got stuck on that screen "system is now locked. Contact your Nissan dealer." I contacted the dealer and they said to put the ignition on and let it on for about one hour, but nothing changed. What can I do to be able to enter the code? I have the code on the unit, but it won't let me due to that error.