MFC Nedbank Theft

My vehicle finance is with MFC division of Nedbank.Due to being unemployed my account went into areas,I recently started work and have been paying my installments,with and additional R1000,MFC has debited my installments of R3900 and the next day R7000.I have been calling them since the 3rd asking them to return my money,they asked for a bank statement I sent that through.These people don't care what your situation is when I was unemployed and even now that I'm working I'm trying to sort my life out and they just without my permission take R7000 from my personal account..this is *****.This is theft.