Frustrated customer

I have been enquiring with FNB for close to two weeks now regarding why my debicheck mandates are automatically rejecting. I’ve been to the FNB branch in Norwood and FNB Sandton City Branch, I’ve called digital banking numerous and no one can find a problem. It’s so frustrating as a customer because now I can’t do contract applications. How is this that I was able to accept my netsar debit mandate earlier in the year but now all of a sudden, I can’t. This is nonsense. I see myself leaving FNB because as a customer, I am very unhappy. Now they busy telling me that they gonna have to do a whole investigation. Im gonna have to wait another two weeks or even more just to get this resolved.