New contract + porting existing iD number = Impossible. Why?

My contract was nearly up with iD, so I decided to pick myself out a new phone. Speaking to someone at Carphone Warehouse, I was told I’d be able to get a better deal on my new phone by cancelling my contract and setting up a new one, so that’s what I decided to do. Of course, I wanted to stay with iD, I LIKE iD. Good plans, good prices, and I could get the phone I wanted, perfect. So today I’ve gotten my new phone and contract, arranged for my old one to be disconnected and been issued my PAC code to port my number over. I put it into the app and… I can’t? Surely there’s something customer services can do so I log onto the live chat. Nope, they can’t either.

So because I decided to stay with iD, get myself a better deal on my new phone AND pay to end my old contract early… I’m being punished as a customer and unable to take my phone number with me to my new contract. To which I want to ask, why? Why can’t I move my old number to my new contract? It really does seem silly for this to be an issue.