Botox RN and MedSpa

I went to Botox Rn on Saturday February 8, 2020 for Dysport Injection which I clearly explained to the receptionist at front. She put me in a room and had me fill out computer form. The injector came in talked to me for a few minutes and started injecting. I asked how much and clearly stated about Dysport and he said it would be about $75.00 and had already been there before 8 months ago and had spent $5000.00. I did not want to spend more than $100.00 on Saturday. When I went to the front to pay she said its $104. I said what. I told her but he said it was only 24 units and she said no it was 32. So I paid $104.00. Later that day she called me and said they made a mistake and I got Botox not what I requested and I needed to pay $200.00 more. How do they make that kind of error!!! I know what I requested and how can they make a mistake. I was extremily upset and I told her that. Also when I went to pay she says "thank you" and I said can I get a receipt. I got a written receipt from their computer but nothing from my debit card and on that receipt it clearly states that I was injected with dysport.