Dstv proof of payment

We had a problem with our decoder, when we phoned to find out what we must do. We were informed that we had money owed to us. As requested, we send 3 month bank statements reflecting when debit order was deducted from my bank account. A month later we are still struggling to get the money from DStv. They asked for proof of payment. How can we get proff of payment from a debit order. I went to the bank and they said they can only help if it was a EFT. I don't know how much more must I proof that that money was paid by us. I don't know!