Deduction of 2 payments in one week on debit order

Account number ***. (Motor Finance) My Debit order went in one payment arrears, I went to the Bank on Wednesday to make arrangements for a change in debit order date, and made my payment. The account was fully paid up to date, with that payment. Wednesday night the bank deducted R 4 129.38 from my account, only because I changed my debit order date to the 15th of May 2015. I cannot understand this, because my account was paid up to date. On Saturday morning I was very upset to see that First National Bank deducted another R 4 129.38, another payment, after I queried this. Again I queried this, but no one, since Saturday called me back, I need the R 8 258.76 back in my account as soon as possible, the Bank stole this monies from me! This is totally unacceptable and I have queried and queried this numerous times! Please help me! They tell me that every query is recorded and that they are going to listen to it and call me back.<br>