36" inch fridge won't fit 36" cabinet void
The fridge's user manual should have clearances / installation dimensions listed. I would start there. It may be a 36" model but actually a slightly different dimension.

If the fridge is not the size described in the manual I would contact the store and/or GE. It's possible that as part of the refurbishing process it was dismantled and not put back together to original factory specs.

Also do not forget to check the required clearances. Most fridges require 1/8" of clearance on the sides, and maybe more at the top and back. (Also you will have a very tough time installing the fridge if there is literally 0 clearance.)