Even if the wiring was incorrect, the teensy should appear as a keyboard to a computer. If you bought the teensy of aliexpress, it is possible that you got a fake version. The original version by PJRC has a smaller bootloader than other ATMEGA32U4 boards, so trying to flash a hex for the teensy won't work if it is a fake. Unfortunately I'm not sure how to tell if it is a fake or not. If it is a fake, you may have overwritten and will need to reflash the bootloader.