Telkom: nightmare changing bank details

I am trying to do a simple thing like change my bank details for my Telkom cellphone and data contracts. I have been calling the shop number of the Telkom shop at Mall of the South for over a month now, not once has it ever been answered.

Yesterday I got time to visit the shop and do it there. When I got there, the "system was offline".

With Vodacom, I was able to do it in a day, over the phone!! This is beyond terrible service.