Hi
I've just come across this thread, because my son is having the same problem. There is clearly a design flaw on the usb connection on these phones, but because Sony won't make it official, O2 declares it as "user damage" and attempts to wash their hands of the problem. For clarification, if you bought your phone from O2, and there was a fault inherent in the phone at the time you bought it, then O2 is responsible in law. They are just repeating, "if it was a known fault, Sony would have told us" until you get bored and pay for the repair.
We're hitting the same problem. Apparently no-one is reporting this as an issue, either to O2 or to Sony. You only have to Google "Sony Xperia USB fault" to see how many issues there are!
Pay for the repair and then sue for the costs back. That's what I will be doing. The total cost to O2 will far outweigh the cost to them of simply doing the repair for free, but that's their choice.
