I never had any problems with Sterlingtek. But quite honestly, it's your fault for not sending it back in a reasonable amount of time. You can't expect any company to accept a return for a product after a year and say that there was a problem with it? I'm sure you are being honest but there are more dishonest people that there are honest people out there.
You're right that it's their fault but I would guarantee you that if you did send it back within, let's say even a month period, they would have replaced it with no problem. But a YEAR?
If they are aware that there was a fit problem with a batch during a specific time, and I am one of those people with a battery that falls under that (would be easy enough for them to tell), I think they should exchange them. But you're right, I waited too long. (Honestly, just forgot about sending them back during a very busy time in my life). On their end, perhaps they should have sent out a recall notice?
If it had been my company I would have taken them back. But that's just me.