Here are information provided by the IRS:
How do I make a complaint against an attorney, enrolled agent, appraiser or a certified public accountant? -- Please direct all complaints to: XXXXX XXXXX ServiceOffice of Professional Responsibility Attn: SE:OPR – Room 7238/IRXXXXX N.W.Washington, DC 20224Or by facsimile at(NNN) NNN-NNNN/em>
What information should be contained in the complaint to OPR? ---- A complaint should be written in a letter format. The letter should include the tax practitioner’s name, address, telephone number, designation (i.e. attorney, CPA, enrolled agent, etc.), a detailed description of the allegations, and any documents that support those allegations.How do I make a complaint against an unenrolled preparer? --- Complete Form 3949-A and mail it to: XXXXX XXXXX Service, Fresno, CA 93888What types of behavior could subject a tax practitioner to be sanctioned by the OPR? --- In general, there are four broad categories of misconduct, which may be subject to disciplinary action: (1) misconduct while representing a taxpayer; (2) misconduct related to the practitioner’s own return; (3) giving a false opinion, knowingly, recklessly, or through gross incompetence, (4) misconduct not directly involving IRS representation.
Here are some comments added by another expert. You may find them helpful:
but you might want to check on the type of tax preparer and the type of complaint. If it's one of the major tax preparation firms, suggest your customer complain up the management chain of the firm. Find out if she wants to make an IRS complaint or just get resolution to an issue. She may just want advice on getting a resolution with her preparer.