Many times a freezer and/or refrigerator do not work right because of a dirty condenser coil...there are also many other things that can go wrong.
If you are hearing a clicking or buzzing then check out the last two tips.
If your refrigerator is running but warm, then...
Check out these tips that I wrote about that... it is a great place to start trouble shooting your unit...and something that you can do rather then calling a repair person to do a simple thing for you...
just bought one that a repair man had already been through with similar issues. i wanted it as a fridge so this was no problem. took me about 5 minutes to figure out the reason it wasn't freezing though...the switch at the top that turns the light on when you open it also turns on the fan when you close the door. the door however sits just a tad too low to fully engage the switch. put a piece of tape over the switch and let it cool for 24 hours. chances are this will solve your problem!
A hum followed by a click sound is an indication of a failure at the compressor. Possibly the compressor motor has gone into a locked rotor condition. A locked rotor condition can be checked using an ammeter. The name plate on the compressor will have a rating after LRA. If the ammeter reading is equal to the LRA rating the compressor is done. If it is a reading of about 80% of the LRA (locked rotor amperage) it is possible that a relay or capacitor has failed which is replaceable.
Either way if you had the doors opened a lot, it should like you probably have frost build up preventing proper air flow. You'd need to pull everything out of the freezer and remove the lower back panel inside the freezer. If there is frost build up, you'll need to use a hair dryer to thaw all the frost out. The unit will continue to beep until the set temperature (0 and 38) are reached so that could take a while even after thawing out all the frost build up.
If removing panels sounds like more than you can handle, you can always unplug the unit for 24 hours and leave the doors open to allow the unit to defrost on it's own.
A Freezer usually has a condensor drain coming out of the compressor, that empties into a condensation dish underneeth, where condensation water is picked up and Re-evaporated.
It is most likely that your Drain is clogged.
Happened to me.
Have someone check your Drain, and if needed unclog it with a small prying tool into the tube.