Delayed time with birthday cake collection

I went to Super Spar Amalinda East London on Friday 29/11/2019 to place a birthday cake order for my son and I was asked the time I'd prefer to collect on the 30/11/2019 which I stated 12:30 as the party was going to start at 13:30. I got into the store at 12:40 to grab 4 items and headed to the till, after making the payment I went to collect the cake. When I got to the counter the young man told me to wait for the Supervisor whom he didn't even bother to call as he preceded to the till to assist a cashier after waiting for 5 min a lady came through. At first she started with the Supervisor story and I told her I don't care who holds what position in the store I am only there to collect my son's cake, I presented the slip to her and when she checked the cake was not there. She asked a staff member to check with bakery, when he came back he said I'll have to wait 15 min which I then asked why did they promise that it'll be ready by the time I requested and I even told them I'm not willing to take any lame excuse as this is the 3rd incident I've had with them. In 2017 my son's name was spelt incorrectly which I do have a pic to prove, 2018 the decorated girl's colors in the school cake and offered to fix it when I went to collect. Yesterday the cake was only made when I went to fetch it. I was so inconvenienced by your *********** staff who kept on screaming to each other on the phone. I was late for my son's party and found my guests impatiently waiting as time is crucial to everyone just like in your business. I forfeited 20min on the venue I paid due to the store mishaps. Ensure that you diarise your customers orders, I'm not the only client who was complaining about this yesterday. I felt like the customer service that the store prided itself with is no longer there, I felt disrespected as a customer. No apology was offered by any of the staff that were involved in this scenario as if I'm supposed to celebrate that my cake was there. I am so disgusted with how I was treated.