Settlement Amount changing

On the 2nd of December, i called standard bank call centre-personal loans division for a settlement amount. Consultant who advised of her system issues, advised she was getting assistance from someone else/team leader. She advised the settlement amount is R13128.43. Payment was made on 3/12/2015. Today, when i call the same division i am advised of a higher amount. Query was escalated to the agents Team Leader Taryn Williams, she said she will be pulling the call. I am utterly disappointed and disgusted with the level of service Standard Bank has provided. This is one of the reasons why i have moved banks due to a low regard for customer service. No one knows what they are doing. I will not be making any other transfer than the payment that has been made. I duly request a settlement letter to be sent. This is the last i wish to have to deal with and endure with Standard Bank. Your settlement amounts are valid for 5 days! Clearly that does not apply to this matter. A prompt and precise response will be appreciated.