Replacement Battery for Dell Active Stylus (750 - AADH) not working

Hey guys, so I have an issue about my stylus that I'd like some help with. So, after having barely used my stylus for over a year, I finally started using it again for taking notes in class. However, there were a few times I thought the battery was starting to die, so I ordered some replacements off of Amazon. Unfortunately, when I tried using them, the pen wasn't working at all. I thought this was a problem with the first battery I tried, but after going through a pack of 12 I realized none of them would work. I tried ordering another set on the off chance I got a bad batch, but the replacement for the replacements came in and those didn't work either.

I'm absolutely positive my pen isn't malfunctioning, since it works when I use the battery that came shipped with it. So I took another look at the batteries I ordered and the default battery that it came with and noticed something strange:

The battery on the left (the one shipped with the pen) has a longer tip than the replacement battery on the right. Is it entirely possible that these replacements aren't making the proper "contact" with the pen, where it can't power it? Is there a "special" type of AAAA battery I need, or am I just having terrible luck with batteries? I don't have a way of testing how much energy's in these things, but I'd assume that at least one in about 20 would have some sort of power in them.

I hope I'm not sounding crazy when I say I need help replacing a freaking battery, so if anyone could help me here I'd really appreciate it.