Lenovo — Lenovo a100

Hello
i am jasim
my phone's contacts is going blank whenever i play clash of clans and comes back after a long time so i deleted all the games including clash of clans and unwanted software but now my phone is still not showing the important contacts it has been 1 day now plss help me lenovo company please ...
and also my phone is hang or stops responding when i am on a call so i cant cut the call and i have to take the battery and keep it again to restart it i buyed my lenovo phone 15 june 2016
the problems have started about 1 and a half month agoooo
so pls help mee i am writing this complaint on 15 april 2017