In a new twist on an old problem with stolen Apple devices, a thief successfully convinced the Apple Store to swap a stolen iPad 2 for a new device with a different serial number, after which Apple refused to help the victim of the crime. iLounge reader Dan Chang says that he purchased a black 64GB iPad 2 with Wi-Fi + 3G from the Apple Store Tysons Corner in May, and the device was stolen less than a week later. Chang filed a police report and was…