Freezer. hope you can help! have a whirlpool freezer, i am not sure of the model number only that

Question

hope you can help! have a whirlpool freezer, i am not sure of the model number only that it is an upright freezer standing 1800 x 600 x 600. Before christmas temperature started to rise i was told it was due to the extreme cold temperatures so i moved it into the house and this cured the problem however in the last few days during the night the temperature started to rise and also occasionally during the day. By turning the freezer off and on again this cures the problem and the pump switches back on and the freezer temperatures lowers again.