Surely a simple action that Financial Service regulators could make ASAP is to require Financial Service Providers to make it easier to lodge a complaint.
I’ve just had to raise a complaint to AmEx. Their complaint process suggests you call them or send a letter (https://www.americanexpress.com/australia/customerservice/resolve_complaints.shtml)
AFCA recommend that complaints be lodged in writing so I think that suggesting people phone to lodge a complaint is a bad idea. If you complain by phone then you have no record of what was discussed.
Surely, if snail mail is the only option to lodge a written complaint they should be required to have a reply paid address.
I ended up emailing them and telling them that I wanted my email treated as a complaint. They ignored this until I actually lodged a complaint with AFCA.
No wonder Financial Service firms are so bad!