FNB Private Client banker Always busy, unable to dispute debit order

Had a bad experience with FNB private client, wanted to dispute an unauthorized debit order and I still have not been able to do so after multiple contact with my private banker as well as service suite. I was not able to dispute a debit order in FNB's award winning app, so i call my banker by clicking the number provided on the app,the call was rejected. So i called their switchboard where i was advised i am being transferred to my banker, after staying on hold i was advised that i will now be transferred to service suite where i was also placed on hold.After waiting 15 minutes i ended the call. Then i received a call from my banker asking me who am I because she received a miss call, told her i want to dispute a debit order. She told me she will not be able to assist at the moment because she is going to some meeting so she will transfer me to "Service Suite" . This banker has used this excuse before when i called to get a bank statement and she advised that she is going to a weekly meeting. Because i know the excuse i hug up and called their service suite . I requested to change the banker as well as dispute.I was advised that the system to make the dispute might be down so i was put on hold while they check after waiting she came back and told me the system is down. The second call also took around 15 minutes. 1. Why allocate me to a banker who is always busy that they have to make up an excuse ?(are they under staffed or am i low priority client ? ) 2.Why didn't the banker know that the system is down ? 3.Why isn't the option to dispute not included in their award winning app?