When on can you feel vibrations come from the drive? If you place your had on the drive it should be very obvious to the touch that it is working.
If you do not feel any movement then it would be the drive is not getting power to it and the blinking is the enclosure letting you know that the drive isn’t accessible. In that situation if the drive is within warranty you can generate an RMA to get a replacement on our site here: RMA
If you do feel movement it could be the enclosure is not sending data back across to the computer. You can check your Disk Utility on the Mac to see if the drive is recognized there. If it is not then it is still hardware failure and it would need to be replaced.
The light coming on is just proof that the enclosure is getting power. Not necessarily the drive itself. That being said did you check the Disk Utility like mentioned?
If you’re not getting any recognition you can try other interface cables if you have another USB cable available but otherwise no recognition means hardware failure.