request for refund

i paid the amount of R600 by mistake on the 28 Aug 2017 and the amount of money that was due for payment was only R300. On the 28 August 2017, the money was paid at Jet in Mabopane shopping centre. On the 23/09/2017 i was at jet colonnade to pay my account that is where they told me that my account was overpaid. On the 04/10/2017 i went to jet at Boulders to ask for refund, they asked for a bank statement and id copy so that they can email them to the big branch, until today no one contacted me and my money is not yet paid.my jet account number is ********** ********** 97736