Unhappy [Q] clone galaxy s4 gt-i9500

hi guys. please help me. i am having a great problem regarding my samsung galaxy s4 clone gt-i9500.. i setted my phone to its factory settings after which everytime i turn on or i turn off my phone instead of the samsung coming out of the screen it woukd be android and then mediatek after. then some of the system apps of the phone could no longer work.. and my most problem of it is that i can longer connect to mobile internet though my network is connected to its 3G/GPRS/MMS connection.. anyone who has the idea how to fix this please help me.. it would be a great help.. thanks so much