I usually keep track of the monthly data usage to avoid exchanging data exceeding the monthly data volume limit. In the old Android 5.x phones, I could set the starting date of the data usage in a month. I check the blogs on Huawei phones, there is such feature is available under the EMUI 3.1 in Huawei Honor Series. (http://www.oxgadgets.com/2015/10/ho...-your-huawei-or-honor-smarphone-emui-3-1.html) However, I am surprised that this useful feature is not available in current EMUI version of P9 Plus. I am disappointed that I am not able to track my data usage at all.