I sent back two iPhones separately as both my wife and I upgraded within a few days. In BOTH cases Mazuma claimed minor additional cosmetic problems (despite my categorising them as only good rather than pristine) and in both cases reduced their offer significantly. Their initial offer was one of the best on a comparison site, their reduced offer falls well below others out there. For this to happen in one instance I could accept but happening in both - and looking at the reviews below - I suspect that Mazuma deliberately inflate their initial offer to get you to use them, and then work on the basis that enough people cannot be bothered to reject a reduced offer once the phone is at Mazuma. Would advise everyone to be very sceptical about their initial offer and go elsewhere.