I had a botched medical procedure and have signed to a year long series of the same procedure?

I had a botched medical procedure and have signed to a year long series of the same procedure. I addressed the doctor and told her i was going to discontinue service with her, she politely agreed to refund my money. Today an attorney representing this very same office contacted me saying that they would not be returning the money. If I have a physical oddity from this very procedure and they are refusing to return my money should I sue them?