Spar do not deal with complaints

I have previously reported to Spar on their Facebook page, that the Spar ultra-pasteurized fresh milk is going off too quickly and forms a sludge in the cup. Their response is to say "inbox me" when I've already reported the problem and they must investigate ... and not bounce me round in circles. There is a definite problem with this product! Don't phone me for a meaningless box ticking exercise.