Really upset and disappointed in the UberEats app and their consultant!!

First time using uberEats and I must say I am deeply disappointed in the app and the extremely horrible consultant claimed his name was Hamid Shakir . I ordered food for the first time using their promo code and confirmed my order but when confirming my order the amount changed to the full amount excluding the promo and it was too late the order was placed I then contacted burgerrack they assisted me in an amazing manner just extremely upset I never got their delicious food because of UberEats and their ridiculous service anyway he informed me that only UberEats could cancel my order for me, i tried canceling as a 'mistake' contacted UberEats and explained what had happened with the promotion why I needed it canceled and the useless consultant Hamid Shakir claiming to call burgerack to cancel my order (as he was the only one that could see to it that my order was canceled) **** and claimed that burgerack did not take his calls and I explained that I just spoke to them and he told me well I can have them call him if I want and I did just that the guy from burgerack said that they never recieved any calls in that time and he called this 'Hamid' UberEats consultant and explained what I needed done as my order had not been sent out yet from the store but the UberEats consultant refused to cancel instead told the guy to send the order out the consultant at UberEats calls me back to tell me that the order had already been sent out (not realising that I had been speaking to the guy at Burgerack) and he will be charging me the same amount as the meal ordered for canceling. This **** of a consultant at UberEats could not even explain why he is charging me that amount after canceling I mean I tried canceling with burger rack explaining my predicament they understood. UberEats service is completely messed up their promos are just a **** as well as their useless consultant because they rip you off in the end!!