Capitec is Ridiculous

I fail to understand why capitec bank cant do a simple thing for me. I went to capitec to try and update my surname from my ****en to my marital surname. So I had my marriage certificate as proof as well as a temp ID as I am awaiting for my ID card. But I was told that they can’t update my surname if I don’t have an ID card. This is really ridiculous and an inconvenience for me. I don’t understand why they can’t update my surname now because the temp ID also comes from home affairs and has all the details they need. Capitec is useless