I know this type of problems with ISPs. In my country, they doing such things too. First you should take a look at your contract, and to something called like General Controact Conditions. I Do not really know how this called english, sorry. Probably youre Personal End User Contract refers to it a lot of times, usually the actual "version" can be downloaded from the ISP's site. By many ISPs, there is a Fair Use Policy limit, that says how much you can download "fairly". If you find nothing like this in neither of those contracts, than it is maybe a more simple case. Usually ISPs doing things (at least by us, in my country) with end users, that is not out of the law, "only" unethical. Just because they can do it. Maybe in your country it is not so, or not common, by us it is. If this is the case, I would advice that you start to search for another internet connection, with another ISP. If they try to fool you once, they will try to fool you more times. Alas, this is the only way for us (end users) to prevent to be threated unethically. Of course this "theory of mine" is based on my experience, so it is probably too much "East-european", so to say.