Customer with buyers remorse

I redo furniture. I purchased two mcm pieces initially she asked if I had a matching set I said no but I could design one in a similar manor, she agreed. She was worried about the color because even in the beginning she seemed apprehensive about doing blue. I send her the color names and swatches as well as photos of the completely pieces. She agreed to accept them and we completed the transaction. She could not be there during drop off, which i have done before when delivering furniture. So she never got to see them in person prior to buying. I receive a message saying she doesn’t like the color blue they are and that googles swatches were deceiving. I offered to change the color out of my own time and money she said yes. Two days later she says she doesn’t want them at all anymore bc she doesn’t trust painted furniture… she bought painted furniture so I was confused how she could pivot so much. When I told her I couldn’t just give her her money back bc of all the money and time I put in I tried to go back to the black solution. She then wanted me to sand down a bunch of drawers and make them wood to match the other tones. For me this was way beyond the original agreement and would require a completely different design. When I felt I wouldn’t be able to satisfy her I told her professionally that I don’t think I can provide her a solution because she was fully aware of the color at time of purchase and rather than voicing her concerns she accepted them. She then threatened to defame my business over it. I’m just kind of at a loss because I feel like I tried to give her as much information as possible. What should I do?