Can i get into any legal trouble if i buy a lot of things from amazon using my free gift cards that i win on beermoney sites?

I have been using appnana for amazon gift cards. My first account stopped accumulating nanas anymore for some reason, so i installed it on my brothers device and made him make a new account. And sharing its code multiple times throughout the day on r/appnana is resulting in a lot of nanas lately. Due to this sudden income from appnana, i am getting a bit concerned about my position if i keep getting nanas in the future and i regularly buy stuffs from amazon, can i get in any kind of trouble doing this? Please do share your experience regarding the "free" purchases you have done from gift cards won from beermoney sites and whether this concern of mine is just unnecessary. Thanks.