Original post by: Minho ,
I thinks it's fair to say that the iPhone 6S you received is not "new". So the question is, where did it come from? If it came from a shop/store or other reputable vendor, I would contact them to let them know there is a problem with the phone. If it came from eBay, you may have some recourse there. If you bought it from someone via a Craigslist or other person-to-person site, then try to reach out the previous owner to understand what the history of the device is. It seems a little unfair that you have to repair this phone unless you bought it knowing it had some issues. At any rate, if you do have to fix it, it sounds more like a charge circuit issue. This could include the [guide|62572|Lightning Port] or the actual charge circuit on the logic board. You have a lot of variables so it's hard to say what is what. Ideally, you will need to eliminate some variables so perhaps trying a new Lightning Port will help you better understand the problem. If that doesn't solve it, then it may be a logic board issue. You may want to consider having a shop look at this as they have all the spare parts to troubleshoot this problem.