I have 3 younger children and of course food may get spilled and splattered on the wall or whatever the case may be. When I try to wipe the wall down and I only use a wet soft cloth paint comes off on the rag. Why is this happening?

We recently moved into a home and the walls were newly painted by the previous homeowner. Over the last few months I have noticed that where the ceiling and the wall meet the paint is cracking and chipping. Could you please give me a reason why this might be happening