I was underwhelmed by the iPhone 6s and for the first time since the iPhone 3g I didn't upgrade. Come the iPhone 7, I was again underwhelmed (particularly lack of headphone jack) and decided to pick up an unused 2nd hand 6s instead. I found a warranty replacement unused phone and it came with a replacement receipt. 3 months later phone presents faults. I go into Apple they give me another replacement. 3 months and 2 days later this one is also faulty. Phone Apple, they give me some tests to run and promise that despite being out of warranty by a couple of days, if it doesn't fix they will replace. Go into store and after a few hours and a couple of managers they eventually get hold of the senior Applecare representative who promised to honour the warranty, so I eventually left the store with another free replacement. Fast forward 2 weeks and I get a call from the particularly unfriendly Apple Store representative who had initially refused to replace the handset. He informed me that the service chain is broken and they don't know where the original handset came from or even the original handset's serial number and do I have a receipt. I explained where I bought it from and offered to provide the previous person's replacement receipt. They said they didn't need this but unless I could provide an original purchase receipt they could not guarantee my phone would activate again after next restore. They confirmed several times that they have no idea which the original phone was as the service chain has been broken. To which I replied that is clearly their problem and what right do they have to block activation of my handset. He again told me to see it from his point of view and threw out some ridiculous justifications. He said he could offer no more help and I should call Applecare. I am still waiting to hear back from Applecare. Anyone here have any advice? Seems a pretty ridiculous situation I am in and one that is completely Apple's fault.