Telkom, an organisation with the same accounting dept of 50yrs ago

I have an LTE contract for many years which is paid by debit order. I simply want to change bank accounts. So i go into a branch with my ID (I've been told the previous time they do not accept a copy on my phone). This time, I've been told they need 3 month's statements!!! So I would have to go a 3rd time to the branch. I also feel they've got no business on knowing how much money there is on my bank account. Proof of banking, I can understand. Telkom is totally outdated in their procedures. Con'on guys try to keep up with modern technology in your accounting dept. I've got an old landline (like from 25 years ago) tied to my name which I tried to remove several times, but their procedures make it unreasonably difficult to do so. So I leave it...databases growing...old leaves on the pavement