Missing products

I bought a family treat yesterday for 10 pieces, R269....boom they gave me 8 pieces. Lodged a complaint yesterday they are saying I must go back to collect it at the shop....nah am not gonna do that....they should refund me my money for the 2 pieces. Am not driving there and waste my petrol. On friday last week i bought the same meal in Tzaneen and the snack burgers were not there they said i must go back, nah they are robbing us deliberately