So yesterday I installed the latest build of windows 10 mobile on my L730 and hard reset it.
I had kept a 8 digit PIN and require sign in was kept at 2 hrs or something ( I don't remember, duh)
I kept the device for charging at night and in the morning I saw this message on my phone after unlocking it using the PIN:
"This device has been locked for security reasons. Connect your device to the power source for at least two hours, and then try again"
My phone is now stuck at this screen but I'm receiving the messages, calls and other notifications but I can't go beyond that screen and use my phone.
I kept my phone for charging in the night so it is pretty obvious that it was connected to the power source for more than two hours..