Proving my income to my bank!

I am a long standing, retired, 77 year old "Prestige"account holder who recently learned that I could switch to a "Consolidated" account and save a lot on bank charges. The call centre asked me to visit the nearest branch to do it. As our local branch had closed, I went to the Somerset mall branch. On my first visit I waited a full hour but saw no one as I had to leave to another appointment. Just a tad irritated! A week later I was very lucky and was seen by a gentleman after a mere 15 minute wait. Hooray! End of happy story. This gentleman asks for proof that I have an income!!! He has access to my bank account which clearly shows my monthly income in hard facts. Not a payslip which can stop when I lose my job, but hard and fast evidence of income derived from regular retirement policy payouts!! I have to get Liberty Life to confirm the amount that is reflected in my bank account for God knows how long. I must go back because it is a few hundred rand a month, but I am really reluctant. No explanation, nothing. Just that is the rule, take it or leave it attitude!