The temperature of the water after the ice has meted is 0 degrees Celsius. Until all the ice has melted and turned to liquid that's the time the temperature of water or liquid increases.
The heat of fusion is the one responsible in changing the phase of ice from solid to liquid.The heat absorbed is used in changing the phase from solid to gas.
Once it turns to liquid the heat absorbed will now increase the temperature of the liquid.
Hope this helps.