Payment not linked to Order and Appaling Customer Experience!

I made an order on 20 May 2018; order ********** and I made an EFT payment. Payment was from my FNB account to their FNB account. On the order confirmation it says that the order will be confirmed on the next business day which was 21 May 2018. I sent through the proof of payment as I did use the order number as the reference but my payment was not allocated to my order. I called in on 21 May and was advised that my payment would be allocated to my order around 3PM and this was not done. I called in today 22 May and spoke to Nomthi Khumalo who said that this is no ones fault and that she will follow up. What? Is this what you call customer service? Appalling! My order is meant to be delivered tomorrow 23 May 2018 and I still expect this to be done as this delay did not come from my side. This delay was due to having 1 person allocating payments who clearly dropped the ball (Nomthi advised that they only have 1 person allocating payments). She said she would get back to me, I am still waiting and there seems to be no urgency with this order. I am shocked at this service as I have never received such delays from this merchant before. I require my order on 23 May as originally scheduled!