Is it just the two wifi and power lights that blink, or all six lights? If all six lights are blinking. . . . that is a “bad sign”. Try rebooting twice (like any other flakey computer device) then try a full reset by pressing and holding both buttons at once… . .then start looking at the RMA process. Just for giggles, plug the device into the wall to make sure it has all the juice it needs.
For the USB cable. . . are you plugging into a computer, or a USB hub? I think this device would be dodgy and act as you describe if you are using a non-powered USB hub. I would try again using a powered (one with a power cord to the wall; not USB bus powered).
For plugging into a computer, try looking at the Device Manager (assuming Windows machine) and see if there are any errors you can clear on the USB ports. (oh. . . .and rebooting the computer once or three times won’t hurt either)