Warning of Promotion

I purchased an item buy 1 get 1 free, there were only two products left, at the till point no discount was given and the full R 720 was due,I then questioned it and eventually was sorted and recieved 1 free, my question is How many people, especially poor pentioners did they catch out that day or during the promotion, how sad and then the answer I got is thay the system did not pick it up. Its not the system or covid to blame, look at the operator and check items befor you claim to sell on promotion, oh and the custercare line is not been answered.