Promo code not app****

I received a promo email of 50% off on Saturday, 26 September. The email said it should be used between 11am and 3pm. I made an order on Saturday, 26 September at 13:35. The R100 discount was app****, and today I saw you deducted the whole amount from my account. I tried to send an email, but I received feedback that seemed like automated responses. Please refund me. As you can see on my order history, I'm a very loyal customer.