Does not change /update details

How long does it take to update your details ?<br> <br> I have changed my bank details due to security as the old account has been compromised, I changed the bank details using the self service option 3 weeks ago. I phoned to confirm but it still pending as AVH pending. I want to change it to cash as I want to pay it monthly manually<br> <br> How long does it take to reflect the changes as the old account will be closed and you guys will debit the old account which will be non existent. Please jack up your socks man.