Pathetic customer service

I was notified by Absa that I was overcharged on the interest on my vehicle loan. I have settled it on full. I was told to email *** which I did. I was phoned by a consultant and told it takes 21 days but there is a backlog. I submitted everything on the 27th of March. it's 5 months later and I'm still battling to get assistance. ***ca then said they would personally help me get this resolved and I still have no joy.