Shabby service from Nedbank

I cancelled my Greenbacks membership around 2 years ago but saw that my account has been charged again for the last 6-7 months. As I am spending a lot more on my cards for that particular account I left the membership active again, however I have not been credited with any of the Greenbacks due to me which should be substantial. I logged a report Ref number ***5 and was promised this would be resolve within 3-5 working days. This.was around 4 weeks and 6 phonecalls ago. I just receive empty promises.of escalation and return follow ups. I have a.big portfolio with Nedbank and have been a client for nearly 40 years. The service is shabby and upsetting and I will consider moving all my accounts incl my investments to another bank if this is not resolved immediately. I can no longer entrust my money to be managed by a bank with clearly substandard service. If this matter is too complicated to resolve, what else is going on there behind the scenes?