Refund of money (40 days late)

I had to settle 2 accounts with standard bank (cheque and personal loan account) which was settled last year april 2014, this year I opened a savings account with standard bank and found that R3700 was debited from my account without any authorisation from myself which happened in May 2015, I then contacted standard bank several times enquiring when will the refund be done, then requested me to contact there legal department and request paid up letters for my cheque and personal loan account which I did, they said that I should received them in 7 days, I only received my paid in full letter for my personal loan account and nothing yet for my cheque account. it has been almost 2 months and I have not received money owed to me. Please can you help me as I have no funds in my account.