Frustrated with RCS Homeloans

I had a home loan with RCS Homeloans which was fully paid on the 5th January 2021. On the 20th January I received notification to pay R1700.52 which was paid immediately. On the 9th April I received my loan statement showing that I am in a credit of R1700.52. I used R100 on airtime trying to get hold of someone to help me getting my money back. I emailed RSC Homeloans but I have not received anymore response. I cannot afford to call RCS Homeloans anymore as I am a pensioner