LA Cie is not recognized by my new Macbook Air

I am so frustrated as my second La Cie backup does not show up on my new Macbook air 26. I have latest software version 26 Tahoe. The La Cie is plugged in and the light is steady and on the backup drive. But my Mac cannot see it. I called Apple support and they had no help except for changing cord and i did that. I have no other computer to use. I guess either Apple has issues with the backup drive OR La Cie (second one in 2 years) is a piece of ****. HELP please.