Beta Keys are no longer working when inputted into Steam

[glossyBag]

I got a beta key a while back but i able unable to use it. I have entered it in EXACTLY (with hyphens), but it still says “The product code you entered is not valid”. BTW i got the code in May 23, 2014
I have pictures if interested, but i do not want to release them to the public eye because they do have beta key codes on them.
Thank you for your consideration.