One little clarification ... and another layer. USBank probably does not do the travel planning, they hire it out. For instance, Chase Ultimate Rewards farmed all the travel out to Expedia many months ago. Most of us had heart attacks, but I called Chase' Travel Desk and they assured me that Expedia did the booking but they would handle any issues. I book mostly hotels with URs, a couple of little flights. No issues yet, so I keep my fingers crossed. I am NOT a fan of any online booking service, save Chase URs, and I trust Chase to bail me out of any problems. So, ultiimately your refund will find its way to USB's travel portal, the cash will be converted to points and re-deposited.So ....you'll get this solved, it would take a great deal of time even in the best economic climate. Now it will take "forever", but you will get your points back.
Here is my understanding, based on lots of points and miles experience. USB slurped up your points and paid cash for your tix. It looks like they paid cash to ANZ ... the code-share part is between ANZ and United and has nothing to do with you or USBank. So United cancelled their leg, United has to refund to ANZ. United should have rebooked you, but we all know that things got a little out of hand in March, so they can't be blamed. ANZ receives UA's cash, then has to refund USBank. USBank will turn that cash refund into points and put them back in your account.
I've not had experience with USBank, isn't that the old Northwest Airlines loyalty plan? I remember transferring my NWA miles to a new Delta a/c because I didn't trust USBank to run things right. They must be doing OK, because they're still operating. I don't know how clever they are managing the program, but if you just keep asking, eventually ... I mean like 6 months maybe, or worse ... the wheels will all turn, one by one, and your points will reappear. Return of loyalty points has gotta be the lowest possible priority right now. So just keep asking, and you must ask USBank. They "own" your tix. Please come back if I'm not being clear. I'd also do a search for a group or forum or something of USBank Flex Perks people; that will allow you to stay on top of things as you go along.