Funny. I have a copy of everything. I also requested them.
Under California law, a patient is entitled to receive a copy of their medical and psychiatric records. This, of course, includes everything, i.e, lab results, diagnosis, surgeries, assesments, history, medication being taken, type of therapy being received, records of conversations between patient and doctor (or medical staff), and letters/medical certificates/other documents issued to patients.
You may want to find out what the laws are in your state and use them to your advantage if your therapist still refuses to give you a copy of this letter you are entitled to have.
tink