Unfair competition

Hi there, i fill up regularly at Osmans BP service station in Matroosfontein, i have entered for the competition numerous times, what i find very unfair is that you have to be there on the day of the draw, you write your name & cell number on the till slip"then they put it in a box" anything can happen that 1 can't attend that day, that's why they have your number to contact you if you are a winner. So unfair, i'll probably start filling up at another brand. Thank you