Pathetic UberEats service

I received an email on Wednesday 02 September about a 50% discount. It included a promo code. I tried entering the promo code on the same day I received the email, but got told that the promo code had expired. I then raised this with UberEats on Twitter and on their app. I'm still waiting to hear from the Twitter account. They had asked me for screenshots of the email - which I provided - but two days later, I'm still waiting. Then, to top it all off, I'm engaging with someone on the app who keeps saying the same thing "At this stage, we are unable to look into this matter further. We understand this is not the resolution you were hoping for." It goes on to talk about how they're constantly aiming to improve their services, but nobody is really saying anything. They keep going back to saying the same thing about the promo code having expired, and I kept having to repeat myself because there's always someone else responding. It's a really pathetic service from UberEats. I'm actually appalled at the responses because it's completely robotic. Absolutely no customer focus at all. What's wrong with you people? You honestly don't care about doing a good job. You're barely even doing your job. And you're getting paid for this? Wow! Shocking!