Your story reminded me of an incident when I worked at a Aquarium Shop and Garden Centre.
One customer kept coming back to the shop getting free goldfish as she kept telling the staff they had died and it was out fault. No other customers had returned with this problem, and the fish on sale were all healthy. I figured she must be taking care of them wrong. I tried to help her by asking questions about her fish tank set up. etc She then changed all her story and said she wanted compensation as this sick goldfish had killed all her expensive Koi Carp in a POND. I was so polite and patient with this woman.......I am just that kind of guy. I said we could maybe do something if she brings in a sample of her pond water so we can do a FREE water test.
Then she goes crazy.....saying she is going to go to all the newspapers telling everyone how the shop is conning people and abusing animals if I don't give her free vouchers and fee koi carp right now! Everyone is looking......I am so embarrassed and ask if she would like to speak to the store manager in her office in private. She then stormed off swearing and shouting.
I was very shaken up. About 20 minutes later I get a call to go to the manager office. The lady had gone to the manager and told her I had been threatening her and swearing at her in front of her child!!!!!!! The sad thing was the manager made me apologise to the woman while she handed her lots of free gift vouchers as an apology from the store! The woman was looking at me with a nasty grin on her face. I was so upset about all that. I even got a disciplinary from the manager on my record, even though the other female assistant working with me told the manager it was not true.
I left that job a few months later.