answer:I believe you’re going to have to provide more details including the type of ISP and living conditions (apartment building, single family dwelling, etc.) Have you changed your password yet, and is there a difference? The most obvious answer is that someone has gotten access to your ISP portal and is using your allotted data. Were I you, I’d make sure the password was changed and if the problem continued I would contact the ISP immediately. They should be able to give you a short list of possibilities and solutions.