EASTMAN KODAK Don't stand behind porducts, Internet

I don't know if you're being very fair. Rechargable batteries are tricky things, if you charge them too often, too soon, not often enough, not soon enough, their life can be greatly reduced, never mind the fact that they sat unused for 6 - 10 weeks.  

Your main issue appears to be that the company won't honor a year long warranty after it had expired. If it's outside the warranty, then that's that. It's not a lifetime guarantee, it's good for one year. That means that whether it breaks 366 days after purchase or 5 years after, it doesn't matter.

If they let you and your 13 months slide because it's only a month after the warranty expired, then they should also let the next guy's 14 months slide because it's only a month after they honored your past due warranty. You see the slippery slope here? The one year mark is just that, a deadline. Sure, it stinks if you fall just to the bad side of the timing, but that happens sometimes. That's life. If this happened 364 days after purchase and they told you no, that's a completely different story.  

What should you do? You buy a replacement battery and call it a day.

Frustrating? Yes. Rip-off? No.

They warranty the batteries for a year, you had the problem after 13 months. It does not matter how long they were just sitting in the camera. Because using that logic what would keep someone from saying that the battery was in the camera for 3 months..6 months..and then try to claim a warranty issue after 15 or 18 months?

Had you returned the battery WITHIN the year and they didn't honor it you would have a valid complaint. But they are under no obligation to honor a 1 year warranty at 13 months.