@Ricky
Thank you for your answer, but you haven't told me that WILL the Fileserve's system think that my account is shared with many people, and then lead to be terminated automatically? If yes, what should I do to prevent this except just call my ISP, and tell them they suck as I don't have any other choice, no any other ISPs around in my area.
how come some files that are not shared mysteriously disappears and not even showing up on dmca tab?
Call your isp and ask them to switch yours ip to static, my friend pay extra 10 bucks every month just for that.