I made a payment of R400 on my account and instead of cashier debating R400

I made a payment of R400 on my account and instead of cashier debating R400.she debited R4000,03.The company is refusing to refund my money, they are sending me from pillar to post, When I spoke to their call center yesterday they said my money would be in my account within 7 working days, now want to me to go to the bank and do charge back distinct.The transection was done on the 6 June 2025. My account no is 6363 ***