I would probably write a letter to the AZ Dept of Revenue asking them to tell you specifically who you owe money to, the amount, when the debt arose, etc. If you already have this information (which you may), I would also write a letter to the agency or department that the AZ Dept of Revenue says caused the refund to be withheld. My sense is a letter will create a document that will make them research the issue, while a phone call may not. Chances are you will never get someone one the phone that knows anything about your case.
Another idea would be to go in person to the AZ Dept of Revenue or the agency at issue and talk to someone there. This can sometimes be a lot more effective than a phone call. When you deal with these folks, remember to keep the discussion focused on this debt that they say you owe, and not on your tax return. Make them show you documentation of what they are talking about. Get copies of all records they show you and keep them together in a file. The backup for their actions has to exist somewhere. Assuming this was a mistake, you should be able to find it pretty quick.
For this year's tax return, you might want to adjust your withholdings to make sure that you owe a little tax instead of a refund, just to be safe.
Good luck mate.