I wouldn't return it as there's nothing wrong with it except a goofy "reverse polarity" protection scheme. Get some of the rare earth magnets, (mine are smaller in diameter than the positive contact on my AW 2900 flat-tops). Put the magnet on the battery and you'll be good to go. I had to go the magnet route with my Eagletac T20C2 MK II also, to use AW 2900 cells in it. Lots of folks use magnets to use certain cells in certain lights. Those little rare earth magnets are incredibly strong and won't move or shift once stuck on the positive end of the battery. Other guys here will put a small blob of solder on the flat-tops, but unless you've got a really good iron with a pretty high tip temp, I wouldn't risk trying the solder thing, as you could damage the cell if it's not done quick enough. ( 2 or 3 seconds). If you do want to go the more permanent solder solution, do a search here on the forums. Someone posted a brief but effective tutorial on how to apply the solder without cell damage. The magnets do work fine though. Good luck, and enjoy your light!