How can I fix Hotpoint american fridge freezer model MSZ 702 NF?

my fridge freezer started making a beeping noise yesterday sort of like a smoke detector that is running low on battery,every time I open the doors light's come on for few seconds then go off the ice dispenser and water are not working properly and I now think the freezer is starting to defrost.It still goes through the motions with all the normal noises it's supposed to make but sounds as though it's toiling also beeping noise has not stopped .