Many big companies prefer not to have publicly-available email addresses. Some firms offer web forms instead whereas others, such as Sky, prefer customers to phone. (That's actually something that I welcome because phone calls, where discussions can take place, are a vastly more efficient way of solving problems than sending constant streams of emails back and forth).
However a bit of googling suggests that these addresses might work:
[email protected]
[email protected]
[email protected]
But I still think phoning is better!
03442 411 653
(Free if you get your phone service from Sky. Also free if you've got a call package, on either a landline or mobile, that gives you free calls to normal 01 or 02 numbers. The same price as calling 01 or 02 numbers otherwise).