Verrry Bad Service from Webank

I have vehicle finance with wesbank, and they have been debiting from my FNB aacount. I called the call centre in February 2023 to change my bank account details as I no longer bank with FNB. I was given forms to complete and send with my new bank account information, of which I did. The details were never amended and when I followed up with the call centre i was told that webank does not debit from my new bank Discovery bank, which was absurd, till today everytime i call to amend my details, they drop my calls. this is very unacceptable, as i have to keep an account that i no longer need just to have wesbank debit going off from it.