Before you consider filing a legal malpractice claim which is difficult and expensive schedule a meeting with your attorney to discuss your case. Make sure each of you understands the other position. Review your options. If the child support hearing was in Juvenile and Domestic Relations District Court you can appeal within 10 days of the hearing and have a new trial.
I have handled several legal malpractice cases but would not take one where child support was the issue because the court has a lot of leeway to fashion a remedy in those types of cases and part of a malpractice case is proving that the outcome would be in your favor if all of the document you wanted introduced were admitted into evidence.
NOT LEGAL ADVICE. FOR EDUCATION AND INFORMATION ONLY. Mr. Zeigler is licensed to practice in the Commonwealth of Virginia, United States Court of Appeals 4th Circuit, United States Bankruptcy Court (E.D. VA) and United States District Court (E.D. VA). Any comments posted are based on an analysis of only Virginia law or relevant federal law and the limited facts given. There is no implied or actual attorney-client relationship arising from this posting. You should speak with an attorney licensed in your state, to whom you have provided all the facts before you take steps that may impact your legal rights.
To prevail in a malpractice case, you would have to prove that the attorney's conduct fell below the standard of care for an attorney in the community and that his behavior caused you damages. That is a tall burden.
This is general advice based on limited interaction in an online forum. The reply does NOT create an attorney-client relationship. You are strongly advised to seek the advice of an attorney in your jurisdiction after you have presented them with all of the facts.