Was the letter from the US State Department? If so, yep. And keep in mind, if you go back, they may arrest you at the border because DHS has the information also. As an aside, if you get citizenship in another country and retain your US citizenship, you must travel in and out of the US on your US passport. If you renounce your citizenship (which I doubt you’ll be able to do because you’re basing it on financial reasons which is not allowed), you can come in and out on your new country’s passport. I recommend settling the outstanding debt…
Surly, one who knows about these things.
Tax assessments (the final reconciliation of your annual tax return, prepared by the government and sent to you with a refund cheque or a bill) are the best. They’re comprehensive, show all income from all sources, and are the first thing I ask my clients for in matters like this. If somebody has been fudging on their tax returns in such a way as to make the assessments inaccurate, then they will have more problems than just a support variance to contend with. 
Inevitable poke: Which one were you when you were in Saudi Arabia? And now that you’re in Qatar, which one are you presently?