Standard Bank still owes me R600

After paying some debt by agreement my last payment on 26 June 2015, my banking app on my tablet inadvertently paid R600 additional to two people, one of which was Standard Bank.<br> <br> Since then I've been trying to get them to pay me the R600 back, but I get no response. On the phone somewhere in July a lady said it was R599.84, but still nothing happened. Following up only brings silence.<br> <br> Funny how rude Standard Bank was when I did owe them money and how silent and slow they are now when they owe me. It was because of their bad attitude that I left in the first place as a client.