Chelle

Hi all! I don't know if anyone can help me or not... I recently got my Nikon d800 back from Nikon repair and they've changed all my camera settings. I have tried resetting my camera file quality to the large RAW options but can't seem to do this. I can change the image quality to RAW but cannot change the image size to large as the image size option is greyed out (it is stuck on medium size). Can anyone let me know if I am doing something wrong? Thanks in advance! :-)