When can you tell if hair is too curly for extraction during FUE hair transplant?

I went to a clinic in ankara, turkey for hair transplant. Black woman. I was supposed to get 3,000 grafts extracted and they started the proces but stopped at 300 grafts and said that my hair was too curly/coily to exxtract. I confronted the dr about not being upfront about their inexperience with black people hair, he insisted they have had multiple african american patients and my hair was just "different and more difficult" and couldn't tell until during extraction process.