Updated app error resulted in a double payment

On 22 & 23rd October I made numerous early payments on my purchases on Payflex. This was now an updated version of your app. Every time the app gets updated there is some problem with early payments. Each payment that I did had a problem where it either never updated the purchase on the app or it did not deduct off my bank account and was suspended. One of these early payments for R704,75 was now also due the 23rd October and because your app did not update the purchase it was processed through my bank account as well. I thought the double payment would reverse out so waited. Eventually on the 24th to the 25th October all the payments started updating. Except this double payment. So I paid the day before 22/10 and Payflex deducted the same amount on the day 23/10. I waited as the others resolved but then I contacted your call centre to assist and yesterday gave them my bank statement to prove the double payment but my concern is the final payment is going off tomorrow on the 6th November and I have not budgeted for a 5th extra payment as it has all been taken already. It is very very urgent. I am going to get charged a non-payment fee as well. This problem happens when I pay with my FNB card and it needs me to approve it then a fault occurs between the bank and your system.