I had a similar experience as another reviewer here. They offered me a reasonable amount for my iPhone 5s and when I sent it in they even said it was in better condition then I had stated so they would give me $15 more. However, they also said that there was water damage to my facetime camera and that they would need to replace it. I had this phone since it was new and it never came in contact with any water. I was aware of some dust under the front facing camera which I told them if they opened the case and blew it out they would notice that the facetime camera worked perfectly. They refused to try and instead told me I would get $45 less for my phone for them to replace a camera that functionally was working just as the day I bought it.
The idea is pretty good. If you are willing to forgo about $100 to not have to deal with selling your phone on your own. I received $100 less from orchard than what was the going rate for my phone on Kijiji/Craigslist.