Keeps malfunctioning whenever I want to use it

I collected my five drinks for one free and then it lost all my credit. I went in for lunch on ice cream day (free cone) and it malfunctioned. According to the app I have no purchase history?! It just isnt reliable enough. It would t be so bad if you could scan the receipt for entry afterwards since it malfunctions all the time. :-( could do better McDonalds!!

MandyERush about McDonald's, v5.5.1