Hi have a powerpoint fridge/freezer defrosted freezer overnight because warm alarm came on yesterday now the freezer doesn't seem to be getting cold and alarm is still going off ?

Check the condenser coils under the refrigerator. Wash out the coils with spray soap and water from hose nozzle. Wash out everything under the refrigerator and put back cover on before turning it back on. This should fix it. Clean these coils once or twice a year.