Having bought four rechargeable batteries, I found that one was a dud. I emailed electronics warehouse and within hours a reply came through indicating that a new pack (not just a single replacement) would be posted ASAP. Two days later they arrived.
Although I was not wanting anything more than just one new battery, to receive a complete pack, without any argument, shows that they have the customer's interest at heart.
Thanks
Bob

Approximate cost: $10