Hoping for some guidance please

The fridge space on the construction plans is marked 980mm wide. After the plasterboard was installed, the space only measures 930mm and with the skirting we're left with approx 906mm

I thought gyprock range between 6.5mm to 12mm thick? So even taking the thickest plasterboard, surely we should be left with at least 956mm clear. How did we lose 26mm?
I'm stressing about this because we already bought the fridge which is 908 wide. I'd flagged this to the builder at design stage as I wanted to make sure the cavity is sufficient to fit the fridge. The way it is now, there's no way that fridge will slide in

Am I missing something here?
Thanks