My daughter's hair is extremely tangled?

Okay she has verrry curly hair. It's washed, conditioned and it has a detangler spray in it. The knots are huge and not coming out. I've brushed it and combed it but NOTHING! She just keeps screaming and crying telling me that it hurts. I brush it everyday and everyday its very tangled but today it just seems like it's not going to get untangled. What should I do? Cut it? Please help!!