Please close my account today!!!!

I called Nedbank to close my account. The agent advised that the account balance needs to be less than r20 I then said okay I’ll buy airtime, the agent said they couldn’t cancel when there’s activity and that I need to call back today. I advised that I couldn’t call the next day (today) because I have many many things to do. I then requested to speak to a manager, he put me on hold, came back and said the manager will call me back as she’s just on another manager call. 24 hours later and I’m still waiting on a call back. Poor customer service is the reason I want to close my account