The B2601 (and many other modernish) Kubota HST tractors don’t have a mechanical connection between the steering wheel and the steering mechanisms. As a result the steering wheel will not be indexed the same each time the wheels are pointed straight ahead. The dealer is ignoring you because it is normal.
You can pull the steering wheel 🛞 off and reindex it every time you park the tractor. It won’t matter, as soon as you move the tractor and turn the steering wheel a couple times. If big K used a symmetrical steering wheel, we wouldn’t likely even realize this situation.