Dischem and false advertising

Dischem is so frustrating, bought 4 packs of nappies which was advertised by them and they gladly took my money but noe they are telling us of a system error but some people were able to collect these nappies. How is it a system error that favours others and does not favour us😡😡😡 It's not our fault that your system failed and for the mere fact that you were able to honour some purchases than you must do the same for everyone who purchased. I am very much frustrated