INVALID PROOF OF PAYMENT

I made a payment from Nedbank website and once the transaction was completed I download proof of payment.

Without any doubt in my head that my supplier will question the validity of my proof of payment. They came back "We cannot accept records of payment as it is not a valid POP, even on the document sent through it is stated it is not considered a valid POP. May I please ask that you send us a valid POP so we can continue with the delivery. Im shocked beyond words! What madness is this? I do understand there is ***** but Im doing honest business and get the proof of payment from the transaction I just completed???????

Really make me look like a fool! Please can you update your website to provide a valid transaction with a valid proof of payment!