Did you write a written letter to you proncipal stating that you believe that she is 1) dyslexic and 2) that her dyslexia is afversely affecting her education because she .... fill in the blank by describing the ways her dyslexia is creating problems... and 3) that you are requesting specialized reading instruction appropriate for dyslexia. Close by saying, therefore, I am requesting an IEP meeting and evaluation of my child as provided for under federal legislation (IDEA).
If you haven't done this, then you haven't made the official request that triggers the legal timelines and procedures that all schools must comply with under federal laws like IDEA, Section 504, and the ADA.
When you say, "they will not give her special services" -- who said that, in what context and by what means? Was it in an IEP meeting? If so, they must provide a written exanation of why they are turning you down.
Or is this just an oral conversation that you had with someone at school and they said smthg like she's not dyslexic, or she's not that bad, or we don't do that type of instruction?
We need me context to hell you.