Poor Service from Spar 2U Service- Knowles

I logged a query on the Spar 2U app two days ago and have had no acknowledgement of it being received or how it is going to be resolved. I have always had a good experience with this delivery service but on my last order, an *********** staff member failed to substitute one of my items and just cancelled it without informing me. I immediately called the store and the manager sorted it out but I was still unpacking my groceries and on my receipt I realised that another item was also substituted (without me being informed) but it was never even packed. I tried to call the store several times as it was still around 18:30 and it had been about five minutes since Mabongi, the manager, had called me back. My calls went unanswered and the delivery guy came back to bring the one item which had been discussed with the manager. I asked him to please get her to call me when he got back to the store since they were ignoring my calls but she never did. If you check the call log for my number you will see that I called at least ten times. I also logged a query about this on my app and have had no response. I would like to know how I am going to be refunded for the item which I never received. It was not an expensive item but I cannot pay for something I never received. That shopper also needs to be trained properly on customer service. I believe her name was Vassie. When she called me she was busy shouting to other people in the background. She only responded after my third hello. Furthermore, she only informed me about two items being out of stock. The other two she didn't even mention. She canceled the one and supposedly substituted the other one but never packed it. My order was supposed to be delivered between 4pm and 5pm but she only called me at 17:20 and still didn't complete it properly. She clearly was not focused on what she was doing. I'm very disappointed.