OP - I'd agree with seniorjudge and badapple40 that you should have representation, if you're going to be trying to vacate a judgment. If you can't afford counsel, get the most information that you can from legal aid, but also ask legal aid about the possibility of "pro bono" (free) representation or assistance through the State Bar.
One thing to understand about vacating a judgment is that "the whole process" also normally entails going back to square one and litigating plaintiff's claim. Vacating the judgment doesn't mean walking away and never looking back. It means re-starting the litigation. So you still have to think about the credit card debt.
In an early post, you said "The credit card in dispute was removed from my credit as I showed it wasn't mine." That makes me curious as to how there could be any judgment, not because of the service issue, which has been discussed at length, but because of that implied statement of non-liability. If you can prove that you're not culpable, even if you were properly served, you certainly need to find some way to get representation, even if counsel must agree to accept payments over time or after the sale of the house.
And while you've repeatedly stated that you know or were told that there's an existing judgment against you, is there any possibility that judgment was only taken against your ex for a card on which you both were jointly liable? Utah permits a non-served joint defendant to be brought into a case and bound post-judgment.
"Utah Court Rule 71B. Proceedings where parties not summoned.
(a) Effect of failure to serve all defendants. Where the action is against two or more defendants and the summons is served on one or more, but not all of them, the plaintiff may proceed against the defendants served in the same manner as if they were the only defendants.
(b) Proceedings after judgment against parties not originally served. When a judgment has been recovered against one or more, but not all, of several persons jointly indebted upon an obligation, the plaintiff may require any person not originally served with the summons to appear and show cause why he should not be bound by the judgment in the same manner as though he had been originally served with process."
There's more to the Rule, which I won't bother to cite if it's not applicable, but I wondered if it might not be be worth noting. The way the judgment creditor "requires [a person] to appear and show cause" is by serving a summons. It doesn't make complete sense that they're tring to serve a summons on you if there's already a judgment against you, but that's repeated throughout this thread.
If, however, there is a judgment, then they probably are trying to compel you into court for an asset exam. It wouldn't be appropriate to tell you to ignore such an order, if it is served, so I didn't tell you that. On the other hand, unless Leinalani absolutely knows that Utah jails litigants for civil contempt, I personally think that it's rather irresponsible to say that you "could face jail time". I do find that Utah confers that discretionary power, but all states do and "discretionary" is the operative word. The likelihood of it happening to a disabled single parent is too remote for me to contemplate.