Lenono A6000 plus issue

[AC Question]

Hey everyone
I have a Lenono A6000 plus handset running on Andorid 4.4.4
Few apps are installing day by day like
Local alarm (no matter how many times I uninstall it.. still gets installed.
Whatsapp (with light green colored icon )
Cleaner
And other free app of the day ads
I have tried Malware bytes, Stubborn Trojan, Avast, Kaspersky
Even factory reset
If someone can help me please.
Thank you in advance

 

[anon(632115)]

Some sort of malware has injected itself into your system files. You will need to flash the device with the stock ROM