Uber Eats complaint: I was charge for an order I ve placed on the 23rd of January that was not deliver

On the 23rd of January at 7.05pm I ve placed an order through Uber Eats at my local pizza restaurant, The Pizza Room in New Cross.
I had ordered 3 times before over the last 3 months and I was completely satisfied with the service from both The Pizza Room and Uber Eats as food was very tasty and deliverd correctly on time.
I live in a flat in Lewisham less than 1 mile from the restaurant.
The flat is on the ground floor and closest to the main door of the tower block.
Like I had done it every time I ordered food delivery , I waited standing by my bedroom window which is litterally next to the main door of my tower block.
The delivery was due to arrived at 7.50pm, and I though the initial delay was due to the fact that the delivery guy was riding his bike (as stated the app) and not a car or scooter.
After waiting for 30 minutes in vain, I follow the instructions on Uber Eats website and sent the form.
I also called the restaurant to see if they could maybe explained what happened to my order, but although the girl was trying to be helpful, she could not give me an explanation.
I was given a Uber eats customer service telephone number which only works if you posses a merchant number or are a courier.
I received a reply via email from uber eats few minutes later, and with my complete shock they said that the delivery guy waited for 9 minutes by the front door of building where I live and as apparently I did not show up , they would charge me for my order and just ended the email by saying they will not be able to assist me any further.
How can they stated without investigated a bit more that the delivery guy waited by front door, when there is only one front door and I waited next to it for more than 30 minutes!
I still can not believe that this is the only form of customer service they offered.