Poor customer service

Vodacom service's is **** I have a contract with them which I make sure that I pay every month with out fail. But what they are doing now is totally not fair they did not debit my account at the beginning of the month of August and I made sure that I pay using their app but they are saying that I didn't pay R340 I made another payment of R30 to see if there was something wrong with the app. The R30 transaction is reflecting but the big amount they are denying it. I sent them my bank statement as proof that the payment went through but still their account department is not looking in to it instead thy are asking me to make another payment this is the second time they are doing this. I spoke to my bank which proves that vodacom took the money but they are just going around in circles about my payment.