ford ka 2004 cd player serial number M015709?

Hi, please please can U help me to unlock my cd player in my car? I had a problem with regulator of aircondition in my car because it wasn't working properly so I went to the service garage and they've replace that for me but they disconected my cd/radio player and now i don't now the code please help mi.. serial numbur is M015709

Silvia
April 2011