This smells. Anything with any real weight comes certified. They can't prove you received a damn thing (unless they recorded your phone call, oops). Moreover, they can issue all the Ohio warrants they like, you live on a farm just outside Bumphuck West Egypt. You weren't in a hurry to go back to Ohio anyway, you didn't like it.
Not really true on the certified mail piece (though a common misconception). The IRS even sends "pay us" correspondence via regular USPS First Class mail. Lots of "official" business gets conducted via First Class mail, including court papers (which in some cases and in some states can be at least partially served via First Class mail via "nail and mail" rules).