I put in a complaint yesterday, after being told all about the next day replacement, and no mention of that being dependent on stock. And how the terms and conditions state that if a phone wasn't available the next nearest would be sent.
I said that I was giving every opportunity for o2 to rectify the situation, following this I would be writing to the financial ombudsmen with full details.
If I receive a reconditioned phone, which is being delivered to my work, so I wouldn't actually be signing for it, and would be signed for before I saw it, it would be a second miss-sell in the same transaction.
Having previously worked in insurance sales, it is not just what you say, it is the impression given and fair expectation of terms. In no way does it say when they guarantee a product to be replaced, but for an insurance product sold with next day, a week is longer than a fair expectation time. I've sent my details over to a mate who is an insurance lawyer and I'll let you know what I hear back but from what I have told him verbally he says it would appear that o2 are in the wrong.