Upload & Sell: Off
Also, if the offending batteries happened to be Duracell brand, the company will repair or replace your flash at no charge, as per the guarantee on the back of the package. I would have doubted this, but recently had reason to take them up on their guarantee after a single battery in a high-quality headlamp leaked without having been old, discharged, or overheated. I sent Duracell the damaged lamp, leaky battery (which I had to drill to remove), and a URL to verify replacement cost. It took about 10 weeks, but sure enough, Duracell sent me a check for full replacement cost, an apology letter, and a coupon for free batteries. Other than the processing time, there was zero hassle.
I've since looked at the packaging on other brands of batteries to see if a similar guarantee is offered. So far, I haven't seen one, other than on Duracell packages. I hesitate to plug for any brand, but solid customer service deserves a mention, and if your batteries happen to have been Duracell, they will likely deal with the problem for you.