I had identical experience but with Uber Eats.
I was given 18 GBP coupon off any orders over 20 GBP.
So I ended up buying a breakfast delivery from McDonalds for the family, I added the food and the coupon to the order...
The first time I tried the payment my card failed. No idea why... it just said Authorization Failed. Second time round, it went through.
Driver came, and I also left a tip.
About a week later I was doing my household budget and looked at the charge on my account, and it excluded the discount. Once you added in delivery, service charge and the tip, I ended up paying 30%+ more for the food (and didn't have my coupon).
I think this was a genuine dark pattern that they use, although I have no interest in putting it to the test. After a failed payment, they auto remove any applied coupons to your transaction....
About a week later I was doing my household budget and looked at the charge on my account, and it excluded the discount. Once you added in delivery, service charge and the tip, I ended up paying 30%+ more for the food (and didn't have my coupon).
I think this was a genuine dark pattern that they use, although I have no interest in putting it to the test. After a failed payment, they auto remove any applied coupons to your transaction....
This was my first and guess-what, last order.