Hi We are here to support the Firefox for Android web browser for mobile devices using the Android operating system. I do not think that your question is really something that we can help with, but I will try my best. If you have access to the device, you should be able to bring up a log of calls made and received. Within the option of the phone dialler app, there should be the option to view a log (assuming it has been set to log calls). If you do not have access to the device, but do have access to billing (whether paper or online) you may be able to see an itemised bill that shows numbers dialled together with time and date. In both cases, care should be taken as this information can be subject to interpretation and should not be taken as the sole source of information without further data to add context.