Bad Customer Service

I'm so frustrated with the service I received from Nedbank. I requested a paid up letter from Zama on the 16 November 2022 and I was advised to share the proof of payment and off which I did on the very same day, and I was told that the letter will be issued within the next 5 - 7 working day. All to find on Monday Zama didn't do what she was supposed to do. Noluthando only requested the letter on the very same Monday and she will escalate the matter to Zama's resorting line. Up until today no letter has been issued. Today I called to find out why is the delay and I was told that the letter will be issued on Monday the 28th and I want to speak to the senior Nosipho Shelembe told me that they are not allowed what kind of service is this? All the financial institutions has an escalation process, Why Nedbank thinks that we can be easily blocked from escalation? This is my right as the customer to escalate and complain about the service that they provide. I'm so devastated.....