I remember this call. You inquired about buying 2 batteries, asked 10 questions that had answers in the listing itself
This was the red flag in the thread for me, and because of this, I would never trust them or do business with them. I ask questions on the phone and completely ignore the sales text ON THE REGULAR, and as a matter of STANDARD PRACTICE, at least in part because I DON'T BELIEVE A frocking WORD OF IT, EVER.
Further, I want the information as I want the information, and not as some aggressive, asshole marketer wants to give it to me. frock that asshole, is my auto-response. Not aimed at this particular marketer, but if the shoe fits, then... Walks like an asshole duck, quacks like an asshole duck, then it's an asshole duck, is the point here. A lot of these grifters will self-declare if you give them enough rope. They can't help it. You can outline clearly "all the things they should not do" and because they are compulsive manipulators and liars, they will still do exactly what it is that you described as "indicators of a grifter".
A legit businessperson would immediately recognize the serious nature of their mistake, apologize and put some effort into making things right, along the lines of "the customer is always right", which is synonymous with "I really want your business" which translates to "I really want your money". Grifters don't want YOUR money, they just want "money", and no particular person is seen as a source of their hoped-for revenue. For them, it's a numbers game. If you lie to enough people, eventually some will be stupid enough to give the grifter the money he wants. Those that do not fall for the scam, do not count, do not matter, and do not exist. Also, what they say is denigrated and dismissed, which is what is being attempted here. People that can read and see the truth of this grifter's character do not count, do not exist, etc... and the grifter doesn't care for them at all. They intend to grift on the drama of the situation, rather than the "one customer at a time" sales technique that legitimate business people do. This post is a good case study into the character of the grifter, and you can use it as a predictor of what happens when you give the grifter your money, then discover that there is "something wrong" with the product. There will be drama, instead of customer service, and the paying customer will be blamed for violations of the social norms, instead of being "made whole" in the transaction.
I'm curious how forum staff allow this kind of thing to happen here. Other forums I've been on require a certain amount of vetting, and sometimes require the Vendors to pay a fee for selling their products, in order to protect their Members from grifters like this person.