I appreciate any help and advice I can get on my case as I feel I have hit a brick wall with Vodafone. I will try and keep the summary below brief.
In short I sought to upgrade my old 12m contract to a new 12m contract and upgrade my old iPhone 6 to a new iPhone 6s Plus. I placed a pre-order, only to receive a 6s and not a 6s Plus which was delivered around 5 weeks ago now. Phone was returned promptly as possible. Vodafone charged me for the upgrade via direct debit and have yet to refund me for the returned handset. Furthermore they have not rolled back my tariff as I was advised to ask