"Lack of outpatient appointment booking"

My sister was discharged from Western Health a number of weeks ago following a 2 week inpatient admission for a bowel obstruction. The care while she was an inpatient was adequate and she was discharged with the Registrar (who was fantastic) requesting an outpatient appointment in 2 weeks. She was advised that she would be sent a letter to advise of the appointment date. She did not receive it after 2 weeks so she called to inquire with the Outpatient Department. They said her file had no record of a request for an appointment. She still doesn't have an appointment and she has called 5 more times since to try to have it sorted out. The person she spoke to claims that the nurses in the department are not doing what they are supposed to do. My sister really wants to see one of the team that treated her to be followed up as she doesn't feel 100% right. She doesn't want to present at the Emergency Department because she is mindful that it is not an emergency. Today (on her 6th phone call) they've advised that they will call her back tomorrow. If they don't she will be contacting the complaints department. It shouldn't be that difficult to at least book an appointment! !