No worries! Doctors can be quite exasperating. I do hope that your testing gets done soon. In regards to insurance, I know that here in Canada, visual therapy is typically not covered. It can help to stress the point with insurance companies that visual therapy has to be referred by an optometrist or what ever medical person is doing your testingand is under their care.
I found that because of the long standing impact of the Chiari, my progress was slower than expected and that one visit a month with enough progressions of exercises (or none!) was enough to keep me moving slowly forward. There is a movement in the visual therapy world where they expect you to come much more frequently and work with a therapist. I personally found that two sessions a day every day with just me was much more impactful for my progress. Our brains need time to change!