So my friend was in a hurry when she was setting up the passocde for her phone and later she forgot the code.
So she takes it to the service center.

SC guy: Ma'am we have to do bla bla bla. And you will lose your data. It will cost you around $10.

She just came back and later gave me the phone.
*unlocks bootloader *
*flashes a custom recovery*
*delete passcode file*
Phone is now unlocked with all the data intact.

PS: I got a small treat at McDonald's. 😋