Rude staff and kept holding on for 20 minutes trying to resolve it

I am writing to express my severe dissatisfaction regarding an outstanding balance of R101 that your department has invoiced me for, subsequent to a test I had performed.

Key Issues Duplicate Billing: I made a full cash payment of over R7,000 for the service on the day. Despite this significant payment, your accounts system has generated an erroneous bill for an additional R101. I demand that your team immediately verify the R7,000 payment and correct your records to reflect a zero balance.

Poor Customer Service and Inefficient Verification Process: When I called to resolve this billing error today, I had an extremely unhelpful and unprofessional experience with your representative.

Unnecessary Detail: After providing my reference number, telephone number, name and surname and ID number, your representative still insisted on asking multiple, redundant personal questions. This process is unnecessary and feels intentionally obstructive when I am calling you with the necessary details to resolve your error.

Unprofessional Conduct: When I asked for clarification on the outstanding amount, your representative became silent and evasive, giving the distinct impression that speaking with me was an inconvenience. This lack of engagement and professionalism is unacceptable when a customer is calling to sort out an error made by your own department.

Demand for Action I request the following immediate actions:

Correction of Account: The R101 outstanding balance must be cleared immediately after verifying the R7,000 payment. Please send written confirmation that my account balance is R0.00.

Customer Service Review: I ask that you review the call recording for today "this afternoon around 3:30 PM" and address the unprofessional conduct of the accounts representative.

Please ensure this matter is resolved within 2 business days. I expect a call back from a senior accounts manager who is competent in rectifying this situation and trained in providing professional customer service.