I was more wondering why the guy thought you would only get 30 days on re-entry. When my son was made redundant due to covid the company actually didn't close his work permit to allow him time to find alternative work which worked out well as it picked up again and they just restarted him as though nothing happened. Hopefully you get sorted again soon.
If your visa has expired or you did not get a re-entry permit then you can come on a Visa exempt stamp and change it to a Non-O visa whilst you are here if you can fulfil the same conditions as your previous Non-O visa.