Who will help me now?

Seven months ago, I had dental implant and bone graft surgery. The pain has been intense, long-lasting and wide-spread, and the non-dental complications extensive, while the groundwork is not even for the type of replacement teeth I agreed to. The dentist has taken $20,000.00, mocks me and denies my problems, and now refuses to complete or correct his work, has "released" me from his practice and refuses to respond to my attempts to even get my records. What do I do?