Did Home Depot send me a fake battery?

I jumped on the $150 deal for the 12ah Flexvolt battery in early December. Right from the get go I noticed that the run time was around the same as my 9ah's in the same applications. I did not notice the advertised 33% more run time at all. Fast forward to this week and the battery won't charge anymore. It only shows one bar and on the charger both lights are a solid red.