Absolute scam. They offer you a good price and get you to send the phone to them - then they mark the device as damaged and offer you an insultingly low price. My phone was in good condition (I didn’t select the most top option because it was used and I was being honest!) they offered £150 for it (less than I could get selling privately but it’s quicker and easier). Once they received it they offered me £20! For an iPhone! I could sell it at the pub for five times that amount. To add further insult, they also sneakily sign you up for antivirus and VPN software on a direct debit without making it clear they are doing so. Awfully dishonest. Avoid at all costs.