I no longer have access to my registered phone number with Capitec bank

I no longer have access to my registered phone number with Capitec bank. I have been trying for a week to access my capitec banking app but capitec will only send the verification code to the phone number i no longer have access to. When i ask them to change my verification method they tell me i have to do it in the app... BUT I CANNOT ACCESS THE APP because i need the verification code WHICH THEY ARE SENDING TO A NUMBER I NO LONGER HAVE ACCESS to. I seem to be stuck in a very frustrating loop and after a week of emailing phoning and WhatsApping Capitec I am still not able to access my bank account. What do i need to do to sort this out??? I have provided a uk number and an email where they can send the code but they insist they can't.