What can be done about child support difficulties in Arizona (Tucson)?

I am a non-custodial parent, continuing to pay child support via wage assignment (garnishment of a portion of my fixed Social Security disability insurance payments). All my children are of majority and emancipated, but ostensibly I have an " arrears only "case open. The state agency AZ Dept. of Child Support Enforcement (AZ Dept. of Economic Security) has consistently bungled the accounting and multiple modifications. Now that I fall into the category of arrears only, they will not respond to me...i.e. assist me, answer questions, respond to my questions, or give me information, accountings, audits, etc. The court that ordered the payments, modifications etc does not have any payment records. Apparently AXZ contracts the collections and accounting out to a private agency (Maximus, Inc, I believe). I have been treated rudely, abrasively and outright meanly by the individuals at this agency AND I am unable to get information. They treat father as "deadbeats". There seems to be no accountability or oversight. Specific questions are: Are you able and willing to assist me Are they immune from a law suit or other type of action? If an action of some type is possible, is there any reasonable probability that it will cause them to respond, move or "get off the dime". I have contacted the State Ombudsperson, the Attorney General’s Office (both centrally, and one of the assigned AAG's to DCSE, The Governor's office all, so far to no avail. By way of background, despite being disable I am a professional individual and a trained paralegal (EO, Med. Mal. by background) and am able to do both the "footwork" and research that is indicated.