Charges under Supply Goods/Services Act 1982

I have just started a 12 month contract with Virgin for cable broadband only. When i moved i believed i had cable in the new property, but it turns out we have not and we cannot have cable either. Virgin offered to move my contract onto a BT line broadband, but that would mean an additional £250. I have heard that if they cannot provide me with the service I have taken out they are forfeiting their part of the contract and the contract should be terminated. Is this correct? Can they force me to take on another service for £250?

Can somebody give me some advice, it would be much appreciated?