Foshini account paid but being harassed

I have had the worst experience from Foshini. I was owing my account as I lost my job in 2017 , their agent called me & advised me to go to their store to do settle my account and I did as requested. I went to the fix in maponya mall and asked the lady how much I owed & she advised me with the amount , I then paid that amount in full & left the store. Ever since then they have been harassing me with their lawyers telling me I'm still owing. This has affected my credit score and I paid them what I was owing. I'm so disappointed in Foshini as the store agents have also been not assisting with this matter.