품질문제에 대한 이유를 상세하게 설명 부탁합니다.

Bad geometry & many drawing errors. 

There's a seam in the back of the jacket that just disappears. The man's ears look they have been pasted on.

I looked at one of your AI images and I already see an issue. If you zoom in really close you can see a flaw on one of the arms. Its like a piece was chipped off.  Probably other flaws as well.  Again just zoom in really close and you'll probably find other flaws as well.  Just have to be meticulous since AI is not very good at perfection.

More rendering errors in general.

I've pointed out just a few of the issues. Only one would have resulted in a rejection.