Perhaps the most common types of complaints against lawyers involve delay or negligence. This doesn't mean that sometimes you've had to wait for a phone call back. It means that there has been a pattern of the lawyer not responding or taking action for a period of months. The most common complaint I hear about lawyers is poor communication.
When someone is dissatisfied with their current attorney, there has invariably been an interruption in communication in some way. For clients, this can manifest as frustration with their lawyer once they spend 6 to 12 months in a dispute without any significant progress, or without having seen any solution. Clients feel dissatisfied when they feel that there is no strategy to achieve their goals and, again, if the end result is far from what their lawyer initially assured. I realized that many of these complaints were directed at companies doing contingency work.
The client was under the impression that he would be awarded a certain amount of money and that the lawyer would receive a percentage. However, once the case is resolved, the client doesn't come close to the money they were led to believe or expected to receive. You also learn that you are also responsible for certain costs, such as medical bills. So, after everything is paid, the customer ends up getting substantially less than they thought and sometimes even nothing at all.
The ABA is not a disciplinary agency for lawyers and has no authority to investigate or act in response to complaints filed against lawyers. Each state has its own agency that performs that function with respect to attorneys practicing in that state. Look for your state agency in the Directory of State Disciplinary Agencies. Each state has an agency responsible for licensing and disciplining lawyers.
In most states, it's the bar association; in others, the state's supreme court. The agency is more likely to take action if your lawyer hasn't paid you the money you earned in a settlement or lawsuit, made a heinous mistake, such as not appearing in court, didn't do the legal work you paid for, committed a crime, or you have a drug or alcohol abuse problem. The three most common lawyer complaints filed against lawyers are allegations of incompetence, failure to act with reasonable diligence and promptness, and the lawyer has a conflict of interest. You may also want a second lawyer to evaluate the actions of your first lawyer and advise you on paying (or refusing to pay) any bill you receive, file a complaint with your state's law discipline agency, or sue the lawyer for malpractice.