I have QMobile z8 and I have a problem from 2 days

in my androib kitkat version facebook youtube videos is not playing and when i open every app like gallery music qapps all are showing unfortunately has stopped and also when i call from messenger imo wechat etc all are showing unfortunately has stopped and when i on off my mobile it take a lot of time and when mobile is on wifi is not working after 2 or 3 minutes its work and finally it is also not accepted sim card
I reset format my mobile 5 or 6 time but it doesn't work