What is so hard about updating banking details

I changed my banking details and let all my debit order know. Our of all 13, Sanlam is the one I am struggling with. Till today, they are incapable of doing a simple thing. Now tomorrow they will continue to debit an account that no longer exist when they have had 30 days to do ths right thing. They asked me to complete a form, I did. They said even though I am a South African I must complete the parts thats say "if not RSA" cz they are compulsory. So I must magically get a passport number,country of issue etc. Because I use my brain, I obviously did not complete parts that are not applicable to me. I am frustrated cz tomorrow is the 1st, amd when theg dont get their it will still be my problem. What could be so difficult about updating banking details