Unallocated online payment

Did an online payment on the Vodacom app on 27 May and no payment is reflecting. Called the call centre 3 times and they can't find the payment as there was an issue with the app on the day that I did my payment. And now my line is suspended because of an issue with their app that they still kept running knowing that they were experiencing problems. I'm so frustrated because the call centre consultants are so unhelpful and I now need to go into the bank to request proof of payment. I'm annoyed and disappointed in Vodacoms customer service