Default [Q] help.am having problems re-installing apps

Good day peeps.
About a week ago,i was tweaking my phone(tecno m5).I recall that I accidentally deleted two system apps(clock and one other one),and. I also installed a fonts app.the phone is still on stock rom 4.2.2.but it doesn't install apps and games agAin.I have tried both sideloading and the playstore.so I decided to format my phone but the problem persIsted when I go to the App manager the internal storage part appeArs as a grey box wiTh nothing showing while the pre installed. Apps show 0.00b under each App.the device was rooted and I was using exposed framework.but now am. Confused cos I can't install anything evEn live wallpapers.somebody please. Help me.So please what can I do To fix this???