Have you noticed that the micro usb cord that came with the phone is noticeably slimmer at the tip that goes into the phone than your typical micro usb cord.
I have a bunch of micro usb cords that I use in various places including my car that cant insert all the way into the phone without hitting the chrome bezel on the phone. They become unplugged rather easily.
Lol - deal My only suggestion is to make sure it's fulfilled by Amazon and not some other store. You'll notice the charger gets stellar reviews, except for a few that say they had problems with a 2nd party vendor.
I just bought a Car to USB charger and will plug my OEM USB cord into it. Best part is I can just swap USB cords and charge my wife's iPod touch, or her's Sansa, or my S9 Bluetooth headset with the same charger and I'm never without the USB cables in case I need to connect to a PC either.