Getting the run around

On Sunday 13 March I used the cellphone banking service on MTN to access ABSA. I purchased prepaid airtime using the service for R200 for Telkom. THe voucher number for this purchase was displayed very briefly and then then disappeared. I was not able to take down the voucher number. I have contacted the ABSA call centre who said i need to contact Telkom for the voucher number. Telkom then said i need to contact ABSA as they are the service provider and the voucher was purchased through them. I am getting the run around. ABSAs service of purchasing prepaid airtime from them is flawed. All i need is the voucher number that i purchased through them.