The same had happened to me . I had submitted application originally in September 2019, but they had returned it on October 8 , to address of the agency that had handled my initial immigration , instead of sending to sponsor . We had not involved any lawyers for spousal sponsorship . and the package went around and in circles and finally called and asked them to remove any other addresses saved on our files in system and got the package returned to me in February 2020 after a long wait , with reason of a missing a single form on travel history , though all of travel history details were there in application.
I would suggest to check with them once more , the package must be returned back to the sydney office since it was not received. If not then initiate a new application which would save you a lot of time .