Mastercard Monday deal not on mobie app

I am upset with the fact that the Mastercard Monday sale that is openly advertised on the website, does not work with mobile app purchases. The only reason I had to use the mobile app, is because the desktop site wouldn't work. <br> <br> Advertising a 20% off deal but not providing the discount is unacceptable. <br> <br> There is no way of knowing if the discount would be app**** since it is unclear during which stage of the payment process it will be app****.<br> <br> Unimpressed that my query regarding this matter has not been answered.<br> <br> An on-line store which flaunts the fact that it has won a \best service"award should actually strive to give good service.<br> """