OK.... firstly the code given is the correct original code for your serial number.
You need to check your serial number, from the label attached to the metal casing.
I suspect you have provided the correct serial number, and it is probably the case that the radio has been re-coded to another code in the past.
The code is stored in eeprom 24c02, and if you have an eeprom programmer to read the memory contents, I can provide a code from this... If you don't have the equipment to read eeproms, then a radio decoder in your area will be able to help you..