Markam ********** compony

I stop using my account in 2018 and I owed R0.00. In 2019 I started receiving calls from the depths collectors ordering me to pay my account but everytime I asked them how much I owed they gave different figures. Then I told them to go back to markam and what exactly am I owing them. They failed to do so but what they were doing is telling me to pay. Today I checked my clear score and I was shocked to see that I last paid my account in February 2020 and 2019 if full paid. Can they please stop labeling me in that way because I do not owe them anything and I last paid that account in 2018. Now my credit score is affected because of their lousy mistakes. Am not happy at all