Mate, you must be cursed. First you car now you fridge.

I reckon if there is no cooling at all it would be unrelated to the refrigerant/gas itself.  I would have thought it would still provide at least a bit of cooling.

I know very little about fridges, but I'd suspect perhaps a thermostat, compressor motor. Something electrical at least.  Especially as its just has stopped cold (pardon the pun ).

This is a side by side fridge?  Top/bottom would use the same refrigerator cycle (so both would have stopped) where a side by side would have independent ones, would they not?

sounds like the thermostat is buggered if the freezer is still going. but then again im no refrigeration techy