closing of revolving loan

I just called in the call centre to enquire about the settlement amount of my loan, was given the amount and advised that to settle the loan I still need to go to the branch as there will be more interests charged on my account. I am nowhere close to the branches and chances are I will not be for the duration of the month due to work. I've been struggling with std bank which even coursed me to stop banking with them because of all the unnecessary processed that just don't make sense. I do not understand the concept of being charged interest while my loan would have been paid up. I am going to pay the balance of R3100 as this is what I was given by your call centre staff and you need to ensure that my loan is closed as I will not pay for any interests charged after I just paid it up. I am really tired of STD bank I would really like to just get this over and done with so that I can part ways with you guys and forget I ever had any accounts with you. I am really upset and frustrated