Bad service

I am writing to express the bad customer service l have experienced from Nedbank. It was on the 28th of October l sent myself a imali voucher as l desperately needed hard cash. I tried to withdraw the money from the ATM , l could not withdraw the money it gave an error saying INSTITUTION NOT AVAILABLE ,On the second attempt it gave me the same error . I then changed ATM to try to with draw my money , to my surprise the ATM gave me an error the voucher already used .

After this l quickly went to one of their branches to report the issue and l was told they will start to investigate the issue and l will be updated after 7 working days. I called the Nedbank call center l was directed to the people who were instigating my case only to be told that the case has been cancelled because the Nedbank employee who logged my ticket did not use correct details of the ATM. They cancelled my case without even notifying me on the progress . I reopened the case again and l was told that it will be resolved in 3 working days , l called Nedbank again to follow up on the case and l was told it was cancelled , they reopened it again and l am told it will be resolved in 24 hours .

It's now almost a month and Nedbank is just giving me the run around . All l want to know where my money went or if Nedbank was hacked ,if l should stop banking with them as there system is not secure.