Disappointed customer - Uber Eats

I am very disappointed in the service i received from Uber Eats on the 18th of March 2020. I use the service 1-2 times a week. I selected the Mochachos 2 burger special for R59.90 option and another light meal. The amount of R121.70 was debited immediately, thereafter i received a notification that the 2 x burger special is sold out. I proceed to order a new meal and that gets debited. I then submitted a request for the reversal of R59.90 because I did not receive the burgers because they were sold out and I was told that I will not be refunded because it does not reflect on my receipt. I queried as to why then was I charged R121.70 for chicken and strips and not the price of R44.80. This went back and forth over 4 emails and still no joy. It is a small amount , however it is the principle behind it, Why charge me for an item that was sold out and refuse to refund me. The App should not have allowed me to order the special if it was sold out. I am disgusted because i am a loyal customer and always recommending them to friends and family. Will never use them again.