promotion

I was listening to highvield 94.7 this morning when wack head told everyone that Mcdonalds had a promo for a egg ****in and orange juice for R10 for the first 500 people from 8:30 to 9:00am. I went to bruma Mcdonalds by 8:40am. When I asked for my order I was told I needed a coupon, I asked what coupon it was not mentioned on the radio and if you read the board in Mcdonalds it says 6:30 to 10:30am for 500 people but nothing about a coupon I spoke to a manager who said to me that there is nothing she could do. So myself and 3 other customers walked out furious. I feel their promotion was done wrong and not proffessional at all. Please assit me with thiis thank you