Game stores poor management and weak acc security

Game store wrongfully debited +-R3400 in my account between Dember 2020 and January 2020. Only to find out that there is an individual who **********ly bought things at a cartain Game store without my knowledge. Now i managed to get the first R1700 and im still waiting for the other one. and instead on Game stores investigating the case and paying me back my money since i sent them an affidavid telling them about the situation they keep on sending me text about how I owe them R1500 and if I dont pay them in time my account will be handed over. Game store/Makro may you please sort out the mess and pay me back my money because im really sick and tired of you guys harassing me over an issue you failed to prevent. I never bought stuff from you on credit since back in 2017