I was going to sell my iPhone back to my network provider and they offered me the same amount of money as Mazuma but I thought I'd wait a couple of days as I wasn't sure if I wanted to upgrade before my contract ran out. I went back on my network providers website two days later and the price had dropped by £70! Mazuma's price was still the same. So I put my iPhone model in to the search field and asked for them to send a pack through the post to send the mobile to them. It arrived the next day, I packed my iPhone and took it to the post office, sent it off and the next day at 10am I got an email saying they had received the iPhone. By 12pm I received an email from Mazuma saying that the phone had been checked and the money that I was quoted will be in my account the same day. The money went in to my account about an hour later. As long as you do what they ask, remove your iPhone from iCloud, include the delivery note so they know who sent the phone (obvious), then they are very trustworthy.