No invoice available for item collected

I placed an order for collection on 19 April 2019. After NUMEROUS efforts to get the order moved to the correct store, I eventually went to collect this from Makro Alberton on 25 April. After waiting 20 minutes for my item, I left and only realized later that I did not receive an invoice for a kettle that cost R599 which carries a 2 year warranty. I then requested an invoice on NUMEROUS occasions, receiving the same response every week. Surely there must be an invoice matched to the online order to clear it? Else it would still show as outstanding on your system? I have again asked for an invoice 31/05/19 and today I received the standard response: "We have contacted our store an we will revert feedback.". PLEASE can I have an invoice for this product or is it too much to ask?