Poor cooling is generally the outcome of a weighty frost made-up on the evaporator loop. You would not be able to view these coils without discarding a panel on the inner part of your freezer. A right sign is that there is a the availability of any ice build-up on the inner ceiling of the freezer. Such a ice build-up generally indicates an error in the self-defrosting structure.

The refrigerator is made in such a way that it should get self-defrost almost four times in every 24 hour duration in case any part in the self-defrosting system doesn't work properly, the refrigerator starts to cool. ultimately, though, maximum ice builds up on the evaporator cloops that the flowing fan can't move air ovto the coils. When coils become icy then it is not able to send right amount of cool air to the coils which results in less cooling or sometime restrict to cooling. To fix such sort of issues you can contact to your local repair technician such as coolrooms or uprightfreezer which can sort out your problem in no time or your can fix it yourself as well by replacing the coils.