Hello My name is Ian ~ I am not on the site constantly so please be patient whilst waiting for responses to you queries ~~
Is it warm in both the refrigerator side as well as the freezer compartment or just one or the other, secondly can you hear the compressor (motor) running?
OK is the motor hot to the touch?
OK from what you have told me your unit is short of refrigerant or the compressor (motor) is not functioning correctly ~ most likely the former. This is not a job for a diy repair as the engineer is required to pierce the copper pipework and check for both refrigerant and compressor operation using specialised tools. If you need me to find you a good refrigeration engineer let me have your postcode and I will let you have one by return post ~ Ian