Can't convert colours to CMYK in Illustrator

Hi,

Wondered if anyone coloud help me with this?

I have a file that I have had printed for a car wrap and part of the design has two rows of a square shape in it.

The doc colour mode is in CMYK mode and the colour window is showing the CMYK sliders for both rows of the squares. Both of these rows of squares have the identical CMYK values.

When you look at the squares on the screen however you can see the first row is a more blue green that the second row and they have printed this way also.

When I select any of them and go to Edit - Edit Colours, Convert to RGB is greyed out so it is obviously what they are set to,. When I click Convert to CMYK, the next time I go to Edit - Edit colours it is back to greying out Convert to RGB, even if I save the doc straight after I do it.

I now need to print the file again for another car wrap and I dont know how to fix this problem!

Thanks in advance.