Typical Amazon.
Do u have prime?
I would and have done this before as well. When u went in the app for the return, you have to look, they give u an option to call them. Then u actually talk with someone. Tell then your issue and then they might do something. Ive had very good luck with this in this type of situation. I also have prime membership and that helps. You can try the manufacture, but like most of there stuff its 3rd party and that might end up being a $hit show.
If all else fails, might have to just bite the bulett and buy the correct one and use the one u have in your riding mower or something? Lessoned learned.
I also try to stay away from the adding acid to batteries type for that reason and other reasons. Your stuck with them if it goes south on you. Can be a mess and I never had much luck with longevity. Even in my sleds
I've got Amazon Prime, Chase Amazon Visa, and they STILL make you go through hoops for some things. Bought 2 identical pair of shoes, they felt cheap, so I returned both together, exactly as I bought them. Long story short, they only gave me credit for returning one pair even though both were in the same box and on the same return label. Took me over 2 months to finally get it resolved, including 3 different phone calls per the same process you described above. From now on, I'm placing separate orders when buying more than one of the same thing (unless there is some discount).
Also, I just bought a Deka ETC30L battery for the Talon's AUX battery. Ready to install, no games with filling the cells first, and - most importantly - made in the US by East Penn in PA. More money? Sure. But a far better battery and I'm helping keep US workers employed.