steroe is aking for keycode,when i enter the keycode it does not take it?

l had the lights in my ford fiesta finesse 1999 reg changed,the battery was taken out in the process and after that i could not turn on the
stereo in the car,the stereo is asking for my keycode which i looked up in the manual that come with the car,the code is 8114 but when i enter it,the steroe says "wait" and it counts down to 30mins,and when when i enter again it repeats it all over again,can someone please help me out here