Best Buy has been good for me!
I've been buying from Best Buy for over 10 years. They have had their moments in the past, but when it comes to phones, I have had a good experience with my son's iPhone 5C. I bought my sons iPhone 5C on launch day and traded in my old iPhone 4 that I gave to him a couple of years ago. It was super easy, and they were very friendly despite working like crazy that day. I even received an extra $50 credit for my traded iPhone 4 since it was traded on another iPhone!
A couple of weeks later (13 days) I heard that they were giving away a $50 gift card with the purchase of an iPhone 5C, and so I called them about it, and they assured me that that was not a problem. When I arrived, they informed me that they needed to see the receipt and after a couple of minutes, they issued me my $50 gift card.
All in all, I have had a good experience with Best Buy when it comes to iPhones. I spend enough with them to be an Elite Customer, so I have a lot of experience with them. I think that they understand that the days of Brick & Mortar stores are very important in a day that we order most things over the internet. Every time I've had a question on a purchase, they have always worked with me!
Remember, its retail, so give them a chance to make it right, and they probably will.