I do sympathise with your predicament and obvious disappointment. Rejection messages are never going to be popular, especially over uni choices where you have obviously put in so much effort to reach this stage. As others have intimated, there could be a variety of reasons including personal statement, and just the more likely fact that more qualified candidates have applied than their are places. I've heard of AAAA* candidates being rejected in the past by Durham, that have been accepted by Oxbridge colleges, (at least based on predicted grades). If you've been given feedback that is generic, you might request more of a specific breakdown. If not, you could potentially take a year out and try again if you were really set on them (and using your time to perhaps improve your application/PS)