why fined me gold coin to -15

just now i want to download some of the files about quality engineer test, but the system automatically fined me gold coin to -15, my god,what happen to this? I do nothing here. I don't know what I did cause the fine action from the system since I just dowload. by the way, the subject i am fined is "质量工程师考试资料汇总 (希望加精) "