BAD COMPANY FASTA LOANS

I took a loan then settled it off from FASTA LOANS, now Nimble group have been harassing me on paying an extra R1963.48, whenever I ask for a statement that breaks down the amount they refused.so now I have a red flag from FASTA loans which I payed and I have been logging calls with no help but threats THAT MY ACCOUNT WONT BE CLOSED.PLEASE HELP PETER.