False Debit

I had a loan with capitec and paid off the loan in 2013, suddenly R579 is deducted from my account today after 3 years when I call them they tell me the account was not put as settled on the system but a foward payment so now there is still outstanding balance that I must pay, last year I went to them to ask for a loan and they declined because they said the reason that I settled my account before the set date affected my score and I was a risk so what surprised me is that now their system suddenly changed my account was never settled, I stayed on the phone for over an hour but cud not get any help, when I paid them the whole money in 2013 i asked them for a settlement amount they gave me and I paid it all in full now they are telling me they made a mistake that I should pay for now