I bought the above activity Tracker last week and followed the instructions for set up. It does not track steps accurately. Some days it shows a few steps after awhile but on Day had a negative 2 (-2). I read all the instructions helps but none mention what to do if it did not work properly. I did a factory reset and well above 15 minutes required on the instructions. I entered the date, weight and height again and thought it was working because it got up to 149 steps but that's it. I've been all over the house and done several chores and it still reads 149. What should I do?