Absa Vehicle Finance is a ****.

I had paid my vaf account in advance to a balance of R10k which I was planning by on settling this month (February) but they added an unknown charge of R4900 on the morning of the 26th Feb 2023. I have been trying to get hold of them but the call centre people are taking me from pillar to post. All I want is to understand what the charge is for and why would that be when I have paid for 3 months upfront. They must stop with these hidden charges.