WesBank service is pathedic

In 2012 I bought a car at VW through Wesbank, the car was paid up early 2018 and I received my paid up letter 25 June 2018. Fast forward to 03 January 2019, I made a call to First National Bank making a follow up on my paid a letter regarding the loan I had with FNB and since I paid up the loan, the Call Centre Agent asked me if I am aware that my Wesbank account has a credit (I had overpaid my car repayments, so I was entitled to a refund). He then adviced me to call Wesbank directly to request the refund, which I did and before I could get any help I was sent from pillar to post. I was told that a lady by the name Diana Theunissen who was busy with my case was on leave and someone would call me back, this was the 2nd week of January 2019. On the 07 January 2019 just before lunch time I called and I spoke to a lady by the name of Kubashni Naidoo, who requested that I should forward my proof of banking details (bank statement) and ID copy, which I did send the same day at 14:53, which she responded the same day at 15:14 informing that she has received the documents and that a lady by the name of Agnes Gezane will contact me soon regarding the authorization of the refund, to my surprise Agnes never called me back as I was promised. I then decided to make a follow up on 22 January 2019 at 07:22 via email to Kubasni Naidoo at ********** , which she then forwarded my email to Diana Theunissen the same day at 09:11, Diana Theunissen did not reply to the email as requested. I then made a follow up to Diana Theunissen via email at ********** on 24 January 2019 at 07:55, asking if there is any feedback on this matter, she then rep**** to the email stating that my request has been escalated to the relevant department to attend to my query, which I then rep**** to her asking if she has any contact number so that I can make a follow up since I was not receiving any feedback even when I am promised feedback. The question I'm having for WesBank is, how can a big institution like this one struggle with a refund of this nature? Its like their staff doesn't know how to go about doing their job because the service I received was of the lowest quality. Ever since I was paying for the car I never missed a single payment, and now WesBank acts as if I owe them or something, and keep in mind my car is paid up, this is really frustrating and I wonder if I would still go back to them to finance my cars or even recommend it to anyone. This is really ****ing me off because it seems like no one in willing to assist me in anyway.