In the past when I had a dispute with Telstra with false claims made over the phone by the call centre staff, I raised a complaint with the ombudsman and asked why the audio recordings couldn't be listened to. IIRC the ombudsman said they often only kept specific recordings for training purposes and that the rest were never kept (they are recorded but overwritten).
Not sure if it was just specific to Telstra or not but thought I'd mention it anyway.
From memory QF archive calls in the CC for 13 months (I designed it back in the day). After that, only the metadata exists - media will be purged.