If a business does a bad job, you go to the BBB. If an accountant / accounting firm does a horrific job is there anywhere you should go to, to complain?
Every state has a "board of accountancy" and depending on how bad of a complaint you can revoke his charter. Now it wont be a Public Complaint like the BBB but it's a start if you feel you want to write to someone.
accountants usually have "errors and omissions" insurance. Talk to a lawyer if you can prove a pretty strong case. Tell him you will be writing up an article called "I was screwed by Accountant XYZ" and sending it to his local papers. and next time, do your own taxes. I also Have the CPA set you up the first year. Then you can follow it yourself. There are lots of methods for automating your record keeping and reporting.