How do you feel about rich kids who hold you to another standard?

I bought a horse from this girl and initially her dad bought him for her. She’s incredibly spoiled and didn’t pay for him. He was $15K. Anyway I’m self made and my parents don’t help me with finances. I paid for most of him in installments and had one payment remaining to which we pushed the deadline back and there was no contract agreement on it. She texted me demanding the money by 5pm and was being absolutely nasty about it. I told her I’d have it to her by a certain date and she was like “I don’t know if I even trust you to do that.” And she’s claiming she needs it because she has to pay her dad back. Which is a lie. She even started texting people I ride with to tell them I don’t pay for things. Which is a lie. I paid $13000 towards this horse of my own money while her dad paid for everything her entire time of owning him. She’s disgusting and can’t empathize with my situation and she’s out of line. And she’s a grown adult/ 32 yo. She really needs my money to pay her dad back? Please.
How do you deal with spoiled rich people who hold you to a different standard and lack empathy?

How do you feel about rich kids who hold you to another standard?
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