Does ABSA have a serious system fault?

I changed my residential address more than a year ago by using the online banking service. The new address appeared on 3 of my 4 account statements. I took proof of the error on the account statement to Strand branch of ABSA and requested the branch manager in person to find out why this error occurs and to ensure the address is corrected. I was promised that it would be corrected and I would receive feedback on the matter. Now, a month later, the next statement has been received and the address is still not correct and there is no feedback as promised from the manager. Is this the best service ABSA can offer? Could it be that there is a serious fault in ABSA systems? Why is ABSA so unreliable?