Service sucks!

I purchased 2 tvs from Hifi Corp. My installments have always been up to date. My last installment was Sept 2020. My last statement in Sept showed I owed R1001 yet Hifi deducted the full installment of R1628. Now I logged on to my account and it shows I still owe R400?? I have sent numerous emails but they don't seem to be bothered to get back to me. Your service sucks. Please give me back my money you stole from me or I will go to the bank and reverse my last 3 debit orders and then ignore you like you ignore me.