Unfairly Listed

I registered in May 2021 unfortunately lost my job and was unable to continue. , therefore canceled in July 2021 . Only to receive an SMS that I was handed over. Despite numerous attempts to getting an explanation from both companies about what I owe. All I'm getting is banking details and threatening sms . Every time I call College SA, the agency would say Victoria is busy she will get back to me . I contacted Ombudsman and Transunion who advised it is out of their jurisdiction. I need to contact Dpt of higher education however, this doesn't make sense.

I need to understand what this account is for and why was I only notified by Collection Agency Nudebt after three years.