Pathetic customer service

Worst customer service ever and staff that is not knowledgeable at all. I ordered food yesterday using a promo code and the discount did not come off so I immediately pressed cancel order and it came up with an error message, I tried a few times and the same error message came up. I tried all avenues to get assistance, including the Ubereats app and Facebook, I received a message on Facebook asking for my information which I did submit but have heard nothing since. This morning I received an email saying that my order was not R300 which was the minimum spend therefore I did not get the discount, my order was R303 which apparently is not included, the second email said that II should not worry and the voucher is still valid and I can use it again. So why do different staff members have different opinions on the same issue. Is Ubereats just trying to blatantly rob the customer? Because I was 1. Unable to cancel the order 2. Unable to get any assistance whatsoever and today I get 2 very conflicting views. Needless to say I will be using Mr D from now on and I will be encouraging everyone I know to boycott Uber due to them being totally useless and unhelpful. I have proof of the conflicting views