ASTRON False advertising

Good day

Where do I report Astron for false advertising? there is an ad for monster and freshtop where it has 2 monster cans for R31 and you can win a bakkie.this from 1 May to 31 June 2024 I have been to 3 stores and was refused to special and a chance to enter the competition. Stores Astron on Isando road today Boksburg Paul Smit Street yesterday Boksburg Sunward park Kingfisher road.yesterday