I have had this issue since when I first got my iPhone 6 Plus 64GB. The volume in the receiver (while in a call) seems low. I have the volume maxed out and still feel it is low. If I am out in public I really have a hard time hearing the other person. I also have had a occasional problems with apps/iphone freezing for a few seconds before I can start using the phone again. I contact apple phone support and they they will send me a replacement device. They ran some IOS diagnostic test that I performed from my iPhone and it supposedly showed a couple of issues but the Applecare Advisor didn't indicate that he knew what they are relating too. Because I have no way of verifying if the call volume issue is actually an issue or just the result of the way the phone is designed...do they have the right to refuse support and charge me full price of the replacement? I have chosen the Express Replacement Service because I have Applecare+. I mentioned the apps freezing issue is also intermittent and that they is no common time where this occurs. It is completely random when it occurs. These issues are very valid in my opinion and obviously the freezing issue is evident. The call volume issue may not be an issue at all but it is definitely lower the iPhone 4 and 5 that I have compared to in our household. I'm just concerned because they have a hold charge on my credit card for a replacement iPhone. Do they have any right to charge me after I send my phone back to them. I'm just worried they turn around and say there is no issue and charge me. There is no physical or liquid damage. I may just be worried over nothing but thought I would get some advice from others who have had a similar situation arise.