Stopped working properly

Annoyed due to the fact, I really need to be keeping track of my weight right now, the scales are easy to set up and the app that goes with them on your phone is great at first I was excited but now a few days after receiving them they skitz out and tell me I'm either 2 stone lighter than the day before or even less lol I wish but now I've wasted my money because they aren't working properly not showing authenticated results.