@ saby8: Sorry to hear that your daughter's training isn't progressing as expected! You already received a lot of really good advise here! I'd also suggest to talk to the chief flight instructor and your daughters instructor first, before talking to the FAA or FSDO. I have been an instructor myself and I know that some students learn fast and others just need more time to get things accomplished. And I agree on what has been said by Squawk777 that women have a different approach to learning as men do. Perhaps your daughter would be better off with a female instructor.
But one thing I'd like to mention as well since I believe it should/must be also considered (it is a quite important question before you continue to spend more money) does your daughter really want to become a professional pilot? Maybe flying is not what she expected it to be in the first place and perhaps she is afraid of telling you (because you already spend so much money)? I mean from my own experience as a flight instructor I know that learning to fly is also a process of self-awareness and quite a few people realize during their training that flying might not be for them. This is a tough decision to make, and it's a decision that can be made only by the individual him/herself, but it should/must be accepted by everyone! No matter how disappointing it appears to be in the first place (particularly for the parents) but I believe in the end it's probably the best/right decision.
Best of luck to your daughter!