My fridge runs every 30 minutes does not matter level i have the themastate on is this normal

I have a maytag plus fridge model # MTB1956BEW Serial# 11035999UK that was in the house when we moved in 2 months ago. At first there seemed to be no problems but now we have had bags of milk spoil 3 times. We have turned the temp up continually and now it is all the way up with the same results. The freezer is a little over half way and seems to be fine. Is there a solution.

This may be normal. However, check and clean the coils on the outside the refrigerator (on the back, or underneath). Vacuum or brush all dust and debris off. Some refrigerators have the coils in the walls, and cannot be cleaned. Be certain there is air space around the refrigerator so that air moves freely over the coils. Next, check to be certain the door seals all the way around. If it is a frost free type, make certain the coils inside do not have ice accumulating on them and that the fan is working (both inside and outside fans). These, when working properly automatically defrost. If it is not frost free, be certain to defrost it making certain there is not excess ice accumulation on the interior coils... ice is an insulator, believe it or not. Be certain the thermostat is not defective, nor the defrost timer. If it is defrosting too frequently, it will have to run more to keep up. Is the refrigerator near a heat source? I hope this leads you to a solution to your problem.