Well I did give a reason at the end of my post, but to expand on it a little, I personally wouldn't like a public system where someone could search a phone number and for it to return associated details to that number. What would you do with that information if, say, when you entered your number in and it gave my details? Are you going to call me up and ask me to remove your number from my account? You can see how this could go very bad if I didn't comply or didn't know how to.
I'm sure this isn't something you would do, I'm sure you just want your phone number released from the other account, but unfortunately not everyone would be the same and there would more than likely be some heated exchanges
Just drop Fongo a line, they are very good at helping with things like this.