Well I'll acknowledge your post (just to prove that I haven't ignored it) but I regret that I can't come up with any other suggestion for you.
However whenever I've used the telephone support services of major electronics manufacturers (including Sony) I've always found them to be really helpful. Perhaps a call to 08705 237 237 would find a solution for you? (I suggest calling from your landline, which will cost you 10p per minute if you're with BT, as you'll then be able to follow any instructions that Sony might give you about fixing your mobile. Lines are open 0800 to 2000).