I Have A Fridge Freezer But The Freezer Isn't Working But The Fridge Does. Why?

It may be low on freon or there is another issue. Have you cleaned the coils for the unit? If you have an air tank or a compressor you go behind or at least under neath the unit and blow off the coils that the freon runs through as dust will build-up on these and decrease the units efficiency. This should be done at least twice a year. The coil cleaning is the quick cheap fix the freon and anything else you probably need a repairman.