You are experiencing what every downloader gets hit with - a fair use policy. All ISP's are applying such policies because the vast majority of their customers have been complaining about the minority who are causing bottlenecks in the system with excessive downloads. As 80% of all downloads are actually by people sharing stolen music and films, I for one am more than happy that my ISP (Virgin) are penalising those few who are causing my own speeds to be affected. Clearly if you are paying the going rate for your own downloads you have a right to expect a good service but VM will only usually start applying their fair-use policy after excessive downloads. Does that apply to you?
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Do you know that we're all in line for succession to the throne? Really?
Well, if forty-eight million, two hundred thousand, seven hundred and one people died I'd be Queen.