Bad customer experience with online banking

I made an online purchase of 4 for the total of R151 each totalling R600, which then the money went from my available balance to merchant balance for payment, when I woke up yesterday I see another R600 was missing from my account but no notification was presented for the transactions, when I went to the branch they confirmed it was a double charge for the same thing and that they reversed it but would take up to 15 days turn around time, last night made a purchase again and the same thing happend again this morning, so that's a total of R750 to that Nedbank ows me now because of double payment because they decline on their side now they deducting my money again with out any notification but yet this has never happened before to me I've always made these payments with no problems only now, NEDBANK PLEASE FIX YOUR PROBLEM AND REVERSE MY MONEY TO ME I NEED TO FOR MY DAUGHTERS SCHOOL FEES