Hi there ,for some reasons of I don't no but my status bar is hidden behind the top of my screen and im unable to read notification s,also my phone was blocked to voicemail ,when people were trying to ring me ,I managed to take it off voicemail but then ,when people were trying to ring it gave the engaged tone .and now I can't even answer my phone .I have recently started to use GiffGaff ,but I have also downloaded an securitie app etc and it keeps niggling me .I was going to perform a factory reset but my phone won't let me what should I do?