The Department of Revenue probably doesn't owe you a duty of care. Thus, you cannot sue for breach of a duty that doesn't exist (i.e., sue for negligence). Moreover, this is not a class action.
Legal Information is Not Legal Advice My answer provides information about the law based on the limited information provided in the questions asked and is not intended to provide legal advice or opinions, and does not constitute an attorney-client relationship. The answer to the question is for educational and informational purposes only. The law differs in each jurisdiction and may be interpreted or applied differently depending on the jurisdiction or situation. Accordingly, I highly recommend that you consult with an attorney to discuss the details of your problem so you can get legal advice tailored to your particular circumstances.
As frustrating as it is--VERY frustrating--you don't appear to have a case (i.e. there is no cause of action upon which you can sue). Your state's Dept of Revenue likely does NOT have a stautory requirement not to waste your time --or in other words--to be efficient. If they don't have any such requirement you have no grounds to sue. Sorry for the news couldn't be better.
READ THIS BEFORE CALLING OR EMAILING ME: I am licensed to practice before the state and federal courts in Virginia. We have not established an attorney-client relationship unless we have a signed representation agreement and you have paid me. I give a 100% effort to get you on the right track with your issue. Sometimes that means legal educational information, sometimes that means counseling and non-legal guidance. You should speak with an attorney to whom you have provided all the facts, before you take steps that may impact your legal rights. I am not obligated to answer subsequent emails or phone calls unless you have hired me. I wish you the best of luck with your situation.