Dischem Nappy promotion a ****

I am highly disappointed at the Dischem buy 10 disposable nappies and get the 11th one free. I have a 10 month old baby and have been buying nappies from the day she was born. I called in yesterday and was advised that i had bought 7 but they will still check. I get a call today to only hear that I have only purchased 9...NINE???? How when I purchase 2 a month? To think that i sometimes had to go out of my way to go to a Dischem just to make sure i add to the promotion just hurts me. Anyways now i know and will not make that mistake of making Dischem my only option.