Bad customer service

I received bad customer service from DSTV , I made payment for the month of May on the 30th of April and i forgot to put in my reference number on the as proof of which payment was traced and they could pick up it was from me as it was an EFT payment. my problem started when i got disconnected and they said payment was not received, i sent them the proof of payment last week Sunday and i was connected same time and yet today this morning i was disconnected again as they said there was no reference on the payment made. i can account to not putting my reference but this is a huge inconvenience to me as i had to make countless calls to the call center explaining myself over and over again about the same thing. I am highly frustrated and annoyed as i am using money to make these calls for a payment that they can clearly see that it was from me.

I also received a email saying i need to make payment and yet i have paid already. Please advise what needs to be done.

Looking forward to your response.