not happy

I have purchased stuff from home choice, and my payment method was Debit order and apperently they did not deduct money from my account when I called to check if everything because I have got so many calls from them, I spoke to a lady named Nawaal she said everything is fine my account is up to date that was on the 2nd of July 2021, I then received an Sms saying my account is in erreas I don't understand how?, I called again on the 13th of this month then spoke to Bulelwa she said she couldn't help me because she doesn't understand so she transferred me back to Nawaal she then promised that she will ask the manager and get back to me. I had to call back today spoke to Najuwa who told me that theres nothing she can they will have to deduct the money that they dd not take last month this month... I don't understand why is it my fault that they did not debit the money when I have set a debit order payment option.. they my Monthly installment is R376. 42 this month end. they wanna debit R670. 00 where will that money come from? I need this issue to be dealt with I am not at fault they are so they need to fix it. I asked for a reference number for all my calls they don't have