I don't now any 4m olds who drink cold milk or formula..
My 10month old still prefers her liquids warm. She will definitely have a little cold water or milk if teething but that's it. Otherwise its warm. Its totally normal for them and easier on their stomach
Use a cup of hot water and put the bottle in it to warm it. You can get one at any coffee, fast food place etc. Its not spoiled, it's easier to digest and naturally they'd have breastmilk at body temp.