Are the commonwealth bank able to canceled my account without warning?

So I hadn't used my bank account for a while coz i was saving it up at home, but then i got a letter saying "we have closed your account because it has been inactive for a year''. They went on to say "30 days ago you recieved a letter warning you that your bank account would be closed if you didn't pay any money into the account", now I never recieved this 'letter' they were refering to prior to or even after recieving this letter. Can the commonwealth bank do that? is it even legal? By the way I'm in AUS so yeah