Nedbank - worst customer service

Absolutely appalling service from Nedbank. Bought prepaid electricity via the Nedbank app on 26 April 2020. Never received the sms with the digits so decided to phone them the next day, I was told they would investigate and let me know. Even had a chat with an agent on the app to no avail. Eventually went into the branch where a lady assisted me and was very helpful. Received a reference number ***7 and I was told on 19 May 2020 that this query has been resolved and the voucher could now be loaded. Tried loading and voucher did not work.So after almost 4 months this issue has not been resolved, no feedback again from anyone. Emails sent and no response. How is that possible for such a big company to still treat customers like this in this day and age. One thing is for sure I am definitely taking my accounts and everything I have with Nedbank to another bank, this is really unacceptable.